Merge light reveal flag into ambient aod

The light reveal flag never shipped, but ambient aod
is depedent on it. Merge the two to simplify rollout.

Test: atest SystemUITests
Bug: 373844670
Flag: com.android.systemui.shared.ambient_aod
Change-Id: I1cc7d114bffd8309a5278e209c6cea3ce7896f05