Fix issue where cold-start launching an activity from the shade while an...

Fix issue where cold-start launching an activity from the shade while an occluding activity is visible would result in an inescapable black screen.

Fixes: 227341125
Test: use Notify.apk (go/notify-apk) to post a notification that'll launch an activity, then force close Notify, open a Meet call (or other SHOW_WHEN_LOCKED activity), lock the phone, press the power button, pull down the shade, tap the Notify notification, UDFPS, note no inescapable black screen
Change-Id: I57c57cbb156dae79fa46e917285330f07ff7edce