Implement WindowPositionChanged in Labs

[Pdawg-bytes]

A conversation in UWP Community took place earlier today, and we discussed getting an event handler up and running for WindowPositionChanged. It’s a useful handler for creating cool visual effects.

Media example, by rocksdanister.

Desktop_2023.07.14_-_01.50.14.20-1.mp4

(note that this is using IInternalCoreWindow2 WindowPositonChanged, it’s just an example.)

@Arlodotexe said that it may be something that could be added to Labs. What do you all think?