Can't allow camera permissions after denying it

[ericrosenbaum]

Shruti reports that after opening the video sensing extension, she accidentally denied the camera permission. She was then unable to find a way to allow the camera permission.

It looks like on OS 10.13 and lower, it automatically grants permissions, so this is only an issue on 10.14+:

systemPreferences.getMediaAccessStatus(mediaType)
This user consent was not required until macOS 10.14 Mojave, 
so this method will always return granted if your system is running 
10.13 High Sierra or lower.

(from https://electronjs.org/docs/api/system-preferences)

[SteveDoesStuff]

Had this same issue and was able to resolve it:

1. System Preferences > Security & Privacy > Privacy tab
2. Select Camera in the left pane (or Microphone if its access was denied in Scratch Desktop)
3. Check the box next to Scratch Desktop in the right pane
4. Restart Scratch Desktop