[Error] `distrobox assemble create` fails to override boolean flags from false->true when "include" key specified

**Describe the bug**
The "include" keyword has incorrect behavior regarding boolean values.
If `=true` overrides `=false` from the included configuration, it isn't generated in the output.
This doesn't happen if the key is omitted; for instance, if `root` isn't mentioned (default: false), then set `root=true`, there is no issue.

**To Reproduce**
```bash
cat >> bug.ini << EOF
[ubuntu]
image=ubuntu:latest
root=true
nvidia=false
additional_packages="zsh"

[ubuntu-nvidia]
include=ubuntu
root=false
nvidia=true
additional_packages="htop iotop"
EOF
```
then run `distrobox assemble create --dry-run --file bug.ini`. You get an output like this:

```
/usr/bin/distrobox-create --yes --name ubuntu --image ubuntu:latest --root --additional-packages " zsh"
/usr/bin/distrobox-create --yes --name ubuntu-nvidia --image ubuntu:latest --additional-packages " zsh htop iotop"
```

Note the `--root` flag is switched off, but `--nvidia` isn't switch on.

**Expected behavior**

```
/usr/bin/distrobox-create --yes --name ubuntu --image ubuntu:latest --root --additional-packages " zsh"
/usr/bin/distrobox-create --yes --name ubuntu-nvidia --image ubuntu:latest --nvidia --additional-packages " zsh htop iotop"
```

**Desktop (please complete the following information):**

- Are you using podman, docker or lilipod?
`podman`
- Which version or podman, docker or lilipod?
`podman version 5.7.1`
- Which version of distrobox?
distrobox: 1.8.2.2
- Which host distribution?
`ublue-main`
- How did you install distrobox?
Included by default

**Additional context**
Also worth noting the leading space in `--additional-packages` is also probably unintentional.