Hide the alternate bouncer after dismiss actions have run

If we hide the alternate bouncer too early, then
sometimes the dismiss action intent will fail. This
CL moves the logic for hiding the alternate bouncer
after a successful biometric auth to when the keyguard
transition to gone is finished.

Flag: None
Flag: ACONFIG com.android.systemui.device_entry_udfps_refactor TEAMFOOD
Bug: 327570518
Test: test with and without udfps_refactor enabled
Test: atest StatusBarKeyguardViewManagerTest AlternateBouncerViewModelTest
Change-Id: I24c98eeec6c76f777033be88ee2d0d54d31e71f4