Adapt all screen previews to recent changes (2/2)

Adapt wallpaper picker screen preview binders and view models to changes
that would allow screen previews to reload when the preview is dirty.

Bug: 270193793
Test: Manually verified anywhere the preview is used
Test: Adjusted view model test to screen preview changes, test still
passes

Change-Id: Idff31e7742d9e94f6758b45de8b1df434c620261