Lock during user switch to secure user during keyguard going away.

This behavior was added in ag/31716364, but not for keyguard_wm_state_refactor code paths.

This adds the locking as well as the notification of the callbacks.

Bug: 341400177
Test: atest SystemUITests
Flag: com.android.systemui.keyguard_wm_state_refactor
Change-Id: I9b1a260a19073d12822cddb02309747eb0d46197