Update dim state when new window is drawn

We used to update the dim state only in prepareSurfaces, but this lead
to flickers with windows that were showing during a transition. Therefore,
when a new window is drawn, we recalculate the state of the possible
affected dim and update it in the same transaction.

Bug: 327332488
Test: DimmerTests
Flag: com.android.window.flags.update_dims_when_window_shown
Change-Id: Idc52a3ee6875218350e34ad44f1c28f6cb5666a1