Also show attached windows during FLAG_SHOW_WHEN_LOCKED animations

Since appShowWhenLocked is already null during the animation, we
also need to show the window if it's attached to a
FLAG_SHOW_WHEN_LOCKED window

Test: Test animation occluded -> lockscreen with an app that
has a SurfaceView
Fixes: 30829255

Change-Id: I0e0012bbe5679cd0894ce4d94902ff8b24823b51