Log a different error when Docker is unavailable on WSL2

### Describe the bug

Below what you currently see when Docker is unavailable on WSL2.
```
(venv) user@vm-win11:~/tmp/beeware/helloworld$ briefcase run --target ubuntu

*************************************************************************
** WARNING: Unable to determine if Docker is installed **
*************************************************************************

Briefcase will proceed, assuming everything is OK. If you
experience problems, this is almost certainly the cause of those
problems.

Please report this as a bug at:

https://github.com/beeware/briefcase/issues/new

In your report, please including the output from running:

$ docker --version

from the command prompt.

*************************************************************************

Briefcase was unable to use Docker commands. Check your Docker
installation, and try again.

Log saved to /home/user/tmp/beeware/helloworld/logs/briefcase.2024_02_04-17_57_53.run.log
```

Unfortunately, the current logic assumes that an unavailable Docker will raise an `OSError`.

But in WSL2, it returns a `CalledProcessError` with some useful text:
```
>>> exp = None
>>> try:
... subprocess.check_output(["docker", "--version"])
... except Exception as e:
... exp = e
...
>>> exp
CalledProcessError(1, ['docker', '--version'])
>>> exp.stdout
b"\nThe command 'docker' could not be found in this WSL 2 distro.\nWe recommend to activate the WSL integration in Docker Desktop settings.\n\nFor details about using Docker Desktop with WSL 2, visit:\n\nhttps://docs.docker.com/go/wsl2/\n\n"
```

Same thing happens at the bash prompt:
```
(venv) user@vm-win11:~/tmp/beeware/helloworld$ docker --version

The command 'docker' could not be found in this WSL 2 distro.
We recommend to activate the WSL integration in Docker Desktop settings.

For details about using Docker Desktop with WSL 2, visit:

https://docs.docker.com/go/wsl2/
```

### Steps to reproduce

1. Ensure Docker Desktop is not running
2. Run `briefcase build --target fedora`

### Expected behavior

Error handling provides a more useful message to the user.

### Screenshots

_No response_

### Environment

- Operating System: Windows 11, WSL 2.0.14.0
- Python version: 3.8
- Software versions:
- Briefcase: `0.3.17.dev283+g23daa64e`

### Logs

Log

```
Date/Time: 2024-02-04 18:11:52
Command line: /home/user/tmp/beeware/venv/bin/briefcase build --target fedora

OS Release: Linux 5.15.133.1-microsoft-standard-WSL2
OS Version: #1 SMP Thu Oct 5 21:02:42 UTC 2023
Architecture: x86_64
Platform: Linux-5.15.133.1-microsoft-standard-WSL2-x86_64-with-glibc2.29

Python exe: /home/user/tmp/beeware/venv/bin/python
Python version: 3.8.10 (default, Nov 22 2023, 10:22:35) [GCC 9.4.0]
Virtual env: True
Conda env: False

Briefcase: 0.3.17.dev283+g23daa64e
Target platform: linux
Target format: system

Environment Variables:
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
DISPLAY=:0
HOME=/home/user
HOSTTYPE=x86_64
LANG=C.UTF-8
LESSCLOSE=/usr/bin/lesspipe %s %s
LESSOPEN=| /usr/bin/lesspipe %s
LOGNAME=user
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
NAME=vm-win11
OLDPWD=/home/user/tmp/beeware
PATH=/home/user/tmp/beeware/venv/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/wsl/lib:/mnt/c/Users/user/.pyenv/pyenv-win/shims:/mnt/c/Users/user/.pyenv/pyenv-win/versions/3.9.13:/mnt/c/Users/user/.pyenv/pyenv-win/versions/3.8.10:/mnt/c/Users/user/.pyenv/pyenv-win/versions/3.10.11:/mnt/c/Users/user/.pyenv/pyenv-win/versions/3.11.3:/mnt/c/Windows/system32:/mnt/c/Windows:/mnt/c/Windows/System32/Wbem:/mnt/c/Windows/System32/WindowsPowerShell/v1.0/:/mnt/c/Windows/System32/OpenSSH/:/mnt/c/Program Files/Git/cmd:/mnt/c/Program Files/dotnet/:/mnt/c/Program Files/starship/bin/:/mnt/c/Program Files/Docker/Docker/resources/bin:/mnt/c/Program Files/PowerShell/7/:/mnt/c/Users/user/.pyenv/pyenv-win/bin:/mnt/c/Users/user/.pyenv/pyenv-win/shims:/mnt/c/Users/user/AppData/Local/Microsoft/WindowsApps:/mnt/c/Users/user/.dotnet/tools:/mnt/c/Users/user/.dotnet/tools:/mnt/c/Users/user/AppData/Local/Programs/Microsoft VS Code/bin:/snap/bin
PS1=(venv) \[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$
PULSE_SERVER=unix:/mnt/wslg/PulseServer
PWD=/home/user/tmp/beeware/helloworld
SHELL=/bin/bash
SHLVL=1
TERM=xterm-256color
USER=user
VIRTUAL_ENV=/home/user/tmp/beeware/venv
WAYLAND_DISPLAY=wayland-0
WSL2_GUI_APPS_ENABLED=1
WSLENV=WT_SESSION:WT_PROFILE_ID:
WSL_DISTRO_NAME=Ubuntu-20.04
WSL_INTEROP=/run/WSL/530_interop
WT_PROFILE_ID={4dd1e689-b517-5f39-947d-78e8a8bdf958}
WT_SESSION=ddc343a5-cbe6-4254-9e07-19f61b67b25a
XDG_DATA_DIRS=/usr/local/share:/usr/share:/var/lib/snapd/desktop
XDG_RUNTIME_DIR=/run/user/1000/
_=/home/user/tmp/beeware/venv/bin/briefcase

Briefcase Log:
[18:11:52] subprocess.py:720
>>> Running Command: subprocess.py:720
>>> docker --version subprocess.py:720
>>> Working Directory: subprocess.py:720
>>> /home/user/tmp/beeware/helloworld subprocess.py:720
>>> Command Output: subprocess.py:720
>>> subprocess.py:720
>>> The command 'docker' could not be found in this WSL 2 distro. subprocess.py:720
>>> We recommend to activate the WSL integration in Docker Desktop settings. subprocess.py:720
>>> subprocess.py:720
>>> For details about using Docker Desktop with WSL 2, visit: subprocess.py:720
>>> subprocess.py:720
>>> https://docs.docker.com/go/wsl2/ subprocess.py:720
>>> subprocess.py:720
>>> Return code: 1 subprocess.py:720
docker.py:183
************************************************************************* docker.py:183
** WARNING: Unable to determine if Docker is installed ** docker.py:183
************************************************************************* docker.py:183
docker.py:183
Briefcase will proceed, assuming everything is OK. If you docker.py:183
experience problems, this is almost certainly the cause of those docker.py:183
problems. docker.py:183
docker.py:183
Please report this as a bug at: docker.py:183
docker.py:183
https://github.com/beeware/briefcase/issues/new docker.py:183
docker.py:183
In your report, please including the output from running: docker.py:183
docker.py:183
$ docker --version docker.py:183
docker.py:183
from the command prompt. docker.py:183
docker.py:183
************************************************************************* docker.py:183
subprocess.py:720
>>> Running Command: subprocess.py:720
>>> docker info subprocess.py:720
>>> Working Directory: subprocess.py:720
>>> /home/user/tmp/beeware/helloworld subprocess.py:720
>>> Command Output: subprocess.py:720
>>> subprocess.py:720
>>> The command 'docker' could not be found in this WSL 2 distro. subprocess.py:720
>>> We recommend to activate the WSL integration in Docker Desktop settings. subprocess.py:720
>>> subprocess.py:720
>>> For details about using Docker Desktop with WSL 2, visit: subprocess.py:720
>>> subprocess.py:720
>>> https://docs.docker.com/go/wsl2/ subprocess.py:720
>>> subprocess.py:720
>>> Return code: 1 subprocess.py:720
__main__.py:44
Briefcase was unable to use Docker commands. Check your Docker __main__.py:45
installation, and try again. __main__.py:45

Main thread traceback:
╭─────────────────────────────────────────────────────────────────────── Traceback (most recent call last) ────────────────────────────────────────────────────────────────────────╮
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/integrations/docker.py:199 in _user_access │
│ │
│ 196 │ │ │ # Invoke a docker command to check if the daemon is running, │
│ 197 │ │ │ # and the user has sufficient permissions. │
│ 198 │ │ │ # We don't care about the output, just that it succeeds. │
│ ❱ 199 │ │ │ tools.subprocess.check_output(["docker", "info"]) │
│ 200 │ │ except subprocess.CalledProcessError as e: │
│ 201 │ │ │ failure_output = e.output │
│ 202 │ │ │ if "permission denied while trying to connect" in failure_output: │
│ │
│ ╭───────────────────────────────────────────────── locals ──────────────────────────────────────────────────╮ │
│ │ cls = │ │
│ │ failure_output = "\nThe command 'docker' could not be found in this WSL 2 distro.\nWe recommend to a"+150 │ │
│ │ tools = │ │
│ ╰───────────────────────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/integrations/subprocess.py:123 in inner │
│ │
│ 120 │ │ """ │
│ 121 │ │ # Just run the command if no dynamic elements are active │
│ 122 │ │ if not sub.tools.input.is_console_controlled: │
│ ❱ 123 │ │ │ return sub_method(sub, args, *wrapped_args, **wrapped_kwargs) │
│ 124 │ │ │
│ 125 │ │ remove_dynamic_elements = False │
│ 126 │
│ │
│ ╭───────────────────────────────────────── locals ─────────────────────────────────────────╮ │
│ │ args = ['docker', 'info'] │ │
│ │ sub = │ │
│ │ sub_method = │ │
│ │ wrapped_args = () │ │
│ │ wrapped_kwargs = {} │ │
│ ╰──────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/integrations/subprocess.py:530 in check_output │
│ │
│ 527 │ │ │ self._log_environment(kwargs.get("env")) │
│ 528 │ │ │
│ 529 │ │ try: │
│ ❱ 530 │ │ │ cmd_output = self._subprocess.check_output( │
│ 531 │ │ │ │ [str(arg) for arg in args], **self.final_kwargs(**kwargs) │
│ 532 │ │ │ ) │
│ 533 │ │ except subprocess.CalledProcessError as e: │
│ │
│ ╭───────────────────────────────────── locals ─────────────────────────────────────╮ │
│ │ args = ['docker', 'info'] │ │
│ │ kwargs = {'stderr': -2} │ │
│ │ quiet = False │ │
│ │ self = │ │
│ ╰──────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /usr/lib/python3.8/subprocess.py:415 in check_output │
│ │
│ 412 │ │ │ empty = b'' │
│ 413 │ │ kwargs['input'] = empty │
│ 414 │ │
│ ❱ 415 │ return run(*popenargs, stdout=PIPE, timeout=timeout, check=True, │
│ 416 │ │ │ **kwargs).stdout │
│ 417 │
│ 418 │
│ │
│ ╭────────────────────────────────────────── locals ───────────────────────────────────────────╮ │
│ │ kwargs = {'stderr': -2, 'text': True, 'encoding': 'UTF-8', 'errors': 'backslashreplace'} │ │
│ │ popenargs = (['docker', 'info'],) │ │
│ │ timeout = None │ │
│ ╰─────────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /usr/lib/python3.8/subprocess.py:516 in run │
│ │
│ 513 │ │ │ raise │
│ 514 │ │ retcode = process.poll() │
│ 515 │ │ if check and retcode: │
│ ❱ 516 │ │ │ raise CalledProcessError(retcode, process.args, │
│ 517 │ │ │ │ │ │ │ │ │ output=stdout, stderr=stderr) │
│ 518 │ return CompletedProcess(process.args, retcode, stdout, stderr) │
│ 519 │
│ │
│ ╭──────────────────────────────────────────────────── locals ────────────────────────────────────────────────────╮ │
│ │ capture_output = False │ │
│ │ check = True │ │
│ │ input = None │ │
│ │ kwargs = {'stdout': -1, 'stderr': -2, 'text': True, 'encoding': 'UTF-8', 'errors': 'backslashreplace'} │ │
│ │ popenargs = (['docker', 'info'],) │ │
│ │ process = │ │
│ │ retcode = 1 │ │
│ │ stderr = None │ │
│ │ stdout = "\nThe command 'docker' could not be found in this WSL 2 distro.\nWe recommend to a"+150 │ │
│ │ timeout = None │ │
│ ╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯ │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
CalledProcessError: Command '['docker', 'info']' returned non-zero exit status 1.

The above exception was the direct cause of the following exception:

╭─────────────────────────────────────────────────────────────────────── Traceback (most recent call last) ────────────────────────────────────────────────────────────────────────╮
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/__main__.py:29 in main │
│ │
│ 26 │ │ │ Path.cwd() / "pyproject.toml", │
│ 27 │ │ │ overrides=overrides, │
│ 28 │ │ ) │
│ ❱ 29 │ │ command(**options) │
│ 30 │ except HelpText as e: │
│ 31 │ │ logger.info() │
│ 32 │ │ logger.info(str(e)) │
│ │
│ ╭────────────────────────────────────────────────────────────────────────── locals ───────────────────────────────────────────────────────────────────────────╮ │
│ │ command = │ │
│ │ Command = │ │
│ │ console = │ │
│ │ e = BriefcaseCommandError('Briefcase was unable to use Docker commands. Check your Docker\ninstallation, and try again.\n') │ │
│ │ extra_cmdline = ['--target', 'fedora'] │ │
│ │ logger = │ │
│ │ options = {'update': False, 'update_requirements': False, 'update_support': False, 'update_resources': False, 'no_update': False, 'test_mode': False} │ │
│ │ overrides = {} │ │
│ │ printer = │ │
│ │ result = 200 │ │
│ ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/commands/build.py:115 in __call__ │
│ │
│ 112 │ │ │
│ 113 │ │ # Confirm host compatibility, that all required tools are available, │
│ 114 │ │ # and that the app configuration is finalized. │
│ ❱ 115 │ │ self.finalize(app) │
│ 116 │ │ │
│ 117 │ │ if app: │
│ 118 │ │ │ state = self._build_app( │
│ │
│ ╭───────────────────────────────────────────────── locals ──────────────────────────────────────────────────╮ │
│ │ app = None │ │
│ │ no_update = False │ │
│ │ options = {} │ │
│ │ self = │ │
│ │ test_mode = False │ │
│ │ update = False │ │
│ │ update_requirements = False │ │
│ │ update_resources = False │ │
│ │ update_support = False │ │
│ ╰───────────────────────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/commands/base.py:578 in finalize │
│ │
│ 575 │ │ │ to finalize. By default, all apps will be finalized. │
│ 576 │ │ """ │
│ 577 │ │ self.verify_host() │
│ ❱ 578 │ │ self.verify_tools() │
│ 579 │ │ │
│ 580 │ │ if app is None: │
│ 581 │ │ │ for app in self.apps.values(): │
│ │
│ ╭────────────────────────────────────────── locals ──────────────────────────────────────────╮ │
│ │ app = None │ │
│ │ self = │ │
│ ╰────────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/platforms/linux/system.py:374 in verify_tools │
│ │
│ 371 │ │ """If we're using Docker, verify that it is available.""" │
│ 372 │ │ super().verify_tools() │
│ 373 │ │ if self.use_docker: │
│ ❱ 374 │ │ │ Docker.verify(tools=self.tools, image_tag=self.target_image) │
│ 375 │ │
│ 376 │ def clone_options(self, command): │
│ 377 │ │ """Clone the target_image option.""" │
│ │
│ ╭────────────────────────────────────────── locals ──────────────────────────────────────────╮ │
│ │ self = │ │
│ ╰────────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/integrations/base.py:77 in verify │
│ │
│ 74 │ ) -> ToolT: ╭───────────────────────────────── locals ──────────────────────────────────╮ │
│ 75 │ │ """Confirm the tool is available and usable on the host platform.""" │ app = None │ │
│ 76 │ │ cls.verify_host(tools=tools) │ cls = │ │
│ ❱ 77 │ │ tool = cls.verify_install(tools=tools, app=app, **kwargs) │ kwargs = {'image_tag': 'fedora'} │ │
│ 78 │ │ return tool │ tools = │ │
│ 79 │ ╰───────────────────────────────────────────────────────────────────────────╯ │
│ 80 │ @classmethod │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/integrations/docker.py:153 in verify_install │
│ │
│ 150 │ │ │ return tools.docker ╭─────────────────────────────────── locals ───────────────────────────────────╮ │
│ 151 │ │ │ cls = │ │
│ 152 │ │ cls._version_compat(tools=tools) │ image_tag = 'fedora' │ │
│ ❱ 153 │ │ cls._user_access(tools=tools) │ kwargs = {'app': None} │ │
│ 154 │ │ cls._buildx_installed(tools=tools) │ tools = │ │
│ 155 │ │ ╰──────────────────────────────────────────────────────────────────────────────╯ │
│ 156 │ │ tools.docker = Docker(tools=tools, image_tag=image_tag) │
│ │
│ /home/user/tmp/beeware/venv/lib/python3.8/site-packages/briefcase/integrations/docker.py:212 in _user_access │
│ │
│ 209 │ │ │ ): │
│ 210 │ │ │ │ raise BriefcaseCommandError(cls.DAEMON_NOT_RUNNING_ERROR) from e │
│ 211 │ │ │ else: │
│ ❱ 212 │ │ │ │ raise BriefcaseCommandError(cls.GENERIC_DOCKER_ERROR) from e │
│ 213 │ │
│ 214 │ @classmethod │
│ 215 │ def _buildx_installed(cls, tools: ToolCache): │
│ │
│ ╭───────────────────────────────────────────────── locals ──────────────────────────────────────────────────╮ │
│ │ cls = │ │
│ │ failure_output = "\nThe command 'docker' could not be found in this WSL 2 distro.\nWe recommend to a"+150 │ │
│ │ tools = │ │
│ ╰───────────────────────────────────────────────────────────────────────────────────────────────────────────╯ │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
BriefcaseCommandError: Briefcase was unable to use Docker commands. Check your Docker
installation, and try again.
```

### Additional context

_No response_

Start at docker.py:183 and trace the Docker version check and command execution logged from subprocess.py:720. Reproduce the `docker --version` failure in WSL2, inspect how the returned error and output are handled, and verify that the resulting message provides useful guidance instead of the generic warning.

Written by the indexing model from the issue text.