Region Sampler Wallpaper Colors Implementation

Refactoring Region Sampler to use WallpaperColors/WallpaperManager
instead of Region Sampling Helper so that we can improve performance
metrics by no longer using SurfaceFlinger to sample. This refactor is applied to the lockscreen smartspace and lockscreen clock implementations of Region Sampler.

Bug: 202758428
Test: manual(tested clock and smartspace on white and black solid color
wallpaper), atest RegionSamplerTest, atest ClockEventControllerTest
Change-Id: Id5d16d07885c82e1f756160071cc9df3cf8fcb0f