* feat(webcams): skip video preview if valid input devices stored
Additionally:
- refactor: re-use the existing VirtualBackground_* storage info instead
of creating a new one
- fix: store background choices per deviceId instead of globally
- fix: guarantee background restore attempts are *critical* when
video-preview is supposed to be skipped. We want the preview to be
shown if the previous background could not be restored to preserver
the user's privacy choice
- fix: cameras could not be shared if no previous device info was in
the user's session
- fix: uploaded background images were not correctly restored
- fix: do not spin up virtual bg workers for brightness if it has not
been altered by the user
- refactor: remove old video-provider background restore routine,
centralize it in video-preview
* fix(skip-video-preview): correct storage check and add playwright test and docs
---------
Co-authored-by: prlanzarin <4529051+prlanzarin@users.noreply.github.com>