Reset internal state in DepthController whenever blur gets disabled by battery saver

Other changes: rename property to match its intended use.

Fixes: 402691460
Bug: 381263619
Test: pending unit tests, tracked in b/381263619
Flag: com.android.systemui.bouncer_ui_revamp
Change-Id: I303afaf3699f8e68ec98f6c83ecd4b2e32dc94e6