Use currentKeyguardState for lockscreenVisibility.

Existing logic was replicating currentState, but by combining two flows rather than filtering the main transitions flow. This results in race condition issues if another flow is collecting the first of the two combined flows. I discovered this while testing OCCLUDED -> ALTERNATE_BOUNCER -> GONE, though it could be an issue in other transitions as well.

Good thing we already have a flow for this state!

Test: atest WindowManagerLockscreenVisibilityInteractorTest
Bug: 307976454
Flag: ACONFIG com.android.systemui.keyguard_wm_state_refactor DEVELOPMENT
Change-Id: Ibc8e8ac4078b192af4af0eabc3552b9489ee3da5