Bug report: cannot grant permission when device is missing

If a device is missing, for example, if the computer only has a microphone but no camera device, clicking the "Allow Access" button will directly lead to a "Permission Denied" page, preventing the user from entering the room.

In the worst-case scenario, if a participant has neither a camera nor a microphone and only wants to listen in on the meeting, they should still be able to enter the room properly.

Reproduce the flow with only a microphone, only a camera, and with neither device, starting at the "Allow Access" button and the resulting "Permission Denied" page. Trace the entry path into the room and verify that participants without camera or microphone access can still join as listeners.

Written by the indexing model from the issue text.