media-player: Show volume slider in more cases

[NasaGeek]

Proposed change

Show a disabled volume slider in cases where the device's volume is reported but can't be "set". This is useful for displaying the volume level even if it can't be changed. I'm working on such functionality for the hdmi_cec integration, and it appears to be the case for some other integrations like epson and androidtv_remote.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

hdmi_cec:
  host: <some-address>
  platform: media_player
  devices:
    AVR: 1.0.0.0

Here's my hdmi_cec snippet. Obviously not really applicable to anyone else, but maybe you get the gist?

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

Old look:

New look:

[NasaGeek]

The hdmi_cec functionality to enable this for that integration isn't merged yet.

[github-actions]

There hasn't been any activity on this pull request recently. This pull request has been automatically marked as stale because of that and will be closed if no further activity occurs within 7 days.
Thank you for your contributions.

[cypherbits]

Is this gonna be reopen or a new request?