DO NOT MERGE Partial revert of lowlight animations

This change partially reverts http://ag/21456149, as if the lowlight
state changes quickly while the animation is running, the device may end
up being stuck in a lowlight state.

Bug: 274024126
Test: atest LowLightDreamManagerTest
Change-Id: Ibb326b30a920cef312b08dd43defa8f9ff9de07d