flatpak'ed Camera does not receive device connection/disconnection events

## What Happened

Camera does not receive connect/disconnect events from cameras. This happens when using a setup with two cameras (notebook webcam plus USB camera).

## Expected Behavior

When webcams are connected/disconnected the app should add/remove elements from the list and show/hide the dropdown menu.

## Steps to Reproduce

Doesn't work:
1. Open camera
2. Attach USB webcam
3. Nothing happens

Works:
1. Attach USB camera
2. Open Camera
3. Both devices are detected

### Logs

No additional information appears on the terminal, but [this flatpak issue](https://github.com/flatpak/flatpak/issues/3447) seems to be about the same problem.

## Platform Information

Elementary 6 Daily