[flexiglass] Fix issue where AOD doesn't show up when sleeping from OCCLUDED.

Lockscreen content should stay visible if an occluding app is present but we're in AOD.

Fixes: 393584105
Flag: com.android.systemui.scene_container
Test: receive a call on the lockscreen, go to/from AOD repeatedly - notice that AOD is now visible in this case
Change-Id: I0119f71f1d46e80543329c6de9a9225cb2b2cdd9