Send occluded update for apps dismissing keyguard

In an earlier issue b/355617360 we prioritised the going-away transition
over occluded updates, but that could put keyguard in an inconsistent
state where it believes it is occluded and not showing, leaving the
screen blank until the device goes into aod.

Bug: 373429224
Test: atest CtsWindowManagerDeviceKeyguard
Flag: com.android.window.flags.reduce_keyguard_transitions
Change-Id: I07b74c53de9a77d82c15888a6f95cb2e6ee02b7c