1. Ignore display overlays since we don't want screen decorations
   included in the occlusion

2. Handle occluded region as separate Rects to ensure that disconnected
   Rects in a Region are not considered occluding in the disconnected
   area.

Test: LayerTrustedPresentationListenerTest
Bug: 256993331
Change-Id: Ib0a4b850e2aafb42e206b8728fcc9b6013171f3f