YouTube Music thinks device is mobile when extension enabled

[pseudotsuga-fir]

Description

When this extension is enabled, YouTube Music assumes your device is mobilem even when not using the sideview. This breaks the UI by rendering the mobile UI and prevents background play.

I would guess this issue stems from aggressive device detection techniques by YouTube to prevent users bypassing background playback, which is a feature that is only available to premium users on mobile devices. Side-view could be doing something to trigger mobile device detection such as some metadata or something being sent in the request headers.

How to reproduce

1. Enable the side-view extension
2. Go to music.youtube.com
3. Clear cookies and local/session storage
4. Refresh the page, press play on a song
5. See that UI renders incorrectly for the page

Example

Without extension enabled

With extension enabled

[pseudotsuga-fir]

This issue is certainly the same as #467, I created this issue instead of replying to the thread to add reproduction steps on a specific site