[keyguard_wm_state_refactor] Fix flickering on canceled screen off.

That debounce does not seem necessary with the flag enabled (I tested all AOD -> awake race conditions), and it causes a ton of issues when the WM state is tied to that transition (you see a black screen for 50ms+).

Additionally, starting the AOD transition from LAST_VALUE was causing a single frame of transitionValue(AOD)==1f, which caused an unwanted setLockScreenShown(aodVisible=true) call.

Bug: 278086361
Flag: com.android.systemui.keyguard_wm_state_refactor
Test: manual
Change-Id: Icf5306ccb12ca356f2aa146ee36de915e25d1ea3