Keep LS not visible during screen off.

This keeps the unlocked app content visible during the light reveal screen off animation. Once we're Idle on a keyguard scene (or start a transition from a keyguard scene, in the cancellation case), the lockscreen will be made visible, hiding the unlocked content.

Fixes: 428253107
Test: atest WindowManagerLockscreenVisibilityInteractorTest
Flag: com.android.systemui.scene_container
Change-Id: I7f3fcc25105d526d4df1b48103ccd2dcd05e991d