Update scrims when keyguard gets occluded

We were assuming that a show_when_locked window would always be on
the lock screen when the device sleeps, but its possible that,
when charging, a window may come visible after the device enters
doze.

Ideally this should be handled in window manager but not feasible
in P.

Change-Id: I8a1b5e638a8e84bbea3a91fc4ac94feb6195390e
Fixes: 80647623
Test: manual with app from play store
Test: atest packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java