[Bug] LiveKit does not respect Video Only setting when using experimental separate window

If a user is using the experimental separate window feature when the AV mode is set to Video Only, it is still possible for them to broadcast audio. They need to manually mute themselves in the separate window to be properly muted.

The separate window should be checking the AV mode (`game.settings.get('core', 'rtcWorldSettings').mode`) and check against the values of `foundry.av.AVSettings` and disable audio broadcasting when required.

From my tests, it appears that Audio Only works "correctly," in that other users don't receive it, but the separate window does still show the webcam view as if it's broadcasting so I wouldn't be surprised that it is still sending the video and there's some other mechanism that's preventing it from being displayed.

1. Set the AV mode to Video Only in the AV settings
2. Connect with 2 users
3. On one user, enable the separate window setting
4. Refresh and join the AV when prompted
5. Ensure that the user is unmuted
6. Speak on that user and listen on the other user

The other user will hear the user speaking.

Start at the experimental separate-window AV entry point and trace how it reads `game.settings.get('core', 'rtcWorldSettings').mode` and `foundry.av.AVSettings`. Reproduce the Video Only and Audio Only cases with two users, then verify that the separate window's broadcast behavior and displayed media match the selected mode.

Written by the indexing model from the issue text.