Set visibleRequested false on wallpapers that are going away

visibleRequested isn't being used properly in wallpaper logic.
Because wallpaper logic deviates so far from activity, fixing
it properly will take time. In the mean-time, we can just set
visibleRequested upon transition readiness so that it is at-
least included in the transition properly.

Bug: 350617801
Flag: com.android.window.flags.ensure_wallpaper_in_transitions
Test: open any app from launcher and observe transitionInfo
Change-Id: Ibc149a038a79273b1179f8ea157b1e87234b1e8b