Windows Store edition: disable developer scratch user interface (#9450)
* GUI/Settings: update copyright year
* GUI/Settings/scratchpad: disable scratchpad checkbox and associated controls if running as a Windows Store app. Re #9438.
Because NVDA.AppX does not support add-ons at this tie, disable developer scratchpad controls from Settings/Advanced panel.
* AppX/Advanced panel: address review comments. Re #9438.
Reviewed by Mick Curran (NV Access):
* Removed comment.
* Add dev group but disabled controls within it.