[BUG] cp.get_file returns files with zero length

Description
I have a file, which is in fact a shell script with a binary blob attached to it. That blob begins at about 20KB, right after the script itself (which is a shell script, which means it is a text).
When trying to run:
salt '' cp.get_file salt://myfile /tmp/myfile

I am getting a file with zero length as the result in /tmp/myfile.
I am using pygit2 as the fileserver backend.

Looks like the issue comes from salt/utils/gitfs.py here, line3054:

  3029	    def serve_file(self, load, fnd):
  3030	        """
  3031	        Return a chunk from a file based on the data received
  3032	        """
  3033	        if "env" in load:
  3034	            # "env" is not supported; Use "saltenv".
  3035	            load.pop("env")
  3036	
  3037	        ret = {"data": "", "dest": ""}
  3038	        required_load_keys = {"path", "loc", "saltenv"}
  3039	        if not all(x in load for x in required_load_keys):
  3040	            log.debug(
  3041	                "Not all of the required keys present in payload. Missing: %s",
  3042	                ", ".join(required_load_keys.difference(load)),
  3043	            )
  3044	            return ret
  3045	        if not fnd["path"]:
  3046	            return ret
  3047	        ret["dest"] = fnd["rel"]
  3048	        gzip = load.get("gzip", None)
  3049	        fpath = os.path.normpath(fnd["path"])
  3050	        with salt.utils.files.fopen(fpath, "rb") as fp_:
  3051	            fp_.seek(load["loc"])
  3052	            data = fp_.read(self.opts["file_buffer_size"])
  3053	            if data and not salt.utils.files.is_binary(fpath):
  3054	                data = data.decode(__salt_system_encoding__)
  3055	            if gzip and data:
  3056	                data = salt.utils.gzip_util.compress(data, gzip)
  3057	                ret["gzip"] = gzip
  3058	            ret["data"] = data
  3059	        return ret

Seems in my case the file is wrongly guessed to be text, but in fact, it's not, causing this decode on line 3054 to fail on an exception., resulting in the destination file to be created with zero length and no data.

What I propose is to write that part in slightly different way:

  3050	        with salt.utils.files.fopen(fpath, "rb") as fp_:
  3051	            fp_.seek(load["loc"])
  3052	            data = fp_.read(self.opts["file_buffer_size"])
  3053	            if data and not salt.utils.files.is_binary(fpath):
  3054	                try:
  3055	                    data = data.decode(__salt_system_encoding__)
  3056	                except UnicodeDecodeError:
  3057	                    pass
  3058	            if gzip and data:
  3059	                data = salt.utils.gzip_util.compress(data, gzip)
  3060	                ret["gzip"] = gzip
  3061	            ret["data"] = data
  3062	        return ret

so even wrong guess will not crash it, resulting in file being correctly transferred to destination.

Setup

• on-prem machine
• VM (Virtualbox, KVM, etc. please specify)
• VM running on a cloud service, please be explicit and add details
• container (Kubernetes, Docker, containerd, etc. please specify)
• or a combination, please be explicit
• jails if it is FreeBSD
• classic packaging
• onedir packaging
• used bootstrap to install

Steps to Reproduce the behavior
Create a text file which is of size more than 2048 bytes then append a binary one right after it. Such a way vendors are distributing installers for their products in a single file, which looks like a shell script, but contains the actual software bundled in the very same file.
Then put it on the Salt fileserver which has its backend set to pygit2 and run:
salt '<minion_id>' cp.get_file salt://myfile /tmp/myfile

You will receive file of a zero length with no content. Salt master log will be spammed with the following error:

2023-03-07 23:00:24,755 [salt.master      :1916][ERROR   ][1382964] Error in function _serve_file:
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/salt/master.py", line 1910, in run_func
    ret = getattr(self, func)(load)
  File "/usr/lib/python3.6/site-packages/salt/fileserver/__init__.py", line 629, in serve_file
    return self.servers[fstr](load, fnd)
  File "/usr/lib/python3.6/site-packages/salt/loader/lazy.py", line 149, in __call__
    return self.loader.run(run_func, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/loader/lazy.py", line 1228, in run
    return self._last_context.run(self._run_as, _func_or_method, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/contextvars/__init__.py", line 38, in run
    return callable(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/loader/lazy.py", line 1243, in _run_as
    return _func_or_method(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/salt/fileserver/gitfs.py", line 176, in serve_file
    return _gitfs().serve_file(load, fnd)
  File "/usr/lib/python3.6/site-packages/salt/utils/gitfs.py", line 3054, in serve_file
    data = data.decode(__salt_system_encoding__)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 23076: invalid start byte

Expected behavior
I expect the file being transferred correctly under any circumstances.

Screenshots

Versions Report

Salt Version:
          Salt: 3005.1
 
Dependency Versions:
          cffi: 1.11.5
      cherrypy: unknown
      dateutil: 2.6.1
     docker-py: Not Installed
         gitdb: Not Installed
     gitpython: Not Installed
        Jinja2: 2.10.1
       libgit2: 0.26.8
      M2Crypto: 0.35.2
          Mako: Not Installed
       msgpack: 0.6.2
  msgpack-pure: Not Installed
  mysql-python: Not Installed
     pycparser: 2.14
      pycrypto: Not Installed
  pycryptodome: Not Installed
        pygit2: 0.26.4
        Python: 3.6.8 (default, Nov  8 2022, 11:32:15)
  python-gnupg: Not Installed
        PyYAML: 3.12
         PyZMQ: 20.0.0
         smmap: Not Installed
       timelib: Not Installed
       Tornado: 4.5.3
           ZMQ: 4.3.4
 
System Versions:
          dist: rocky 8.7 Green Obsidian
        locale: UTF-8
       machine: x86_64
       release: 4.18.0-425.10.1.el8_7.x86_64
        system: Linux
       version: Rocky Linux 8.7 Green Obsidian