Fix race condition with 'leaveShadeOpen'

Transition view models capture state on start, including
whether the shade should remain open after unlock. This
could sometimes happen too late, like during
ALTERNATE_BOUNCER->GONE. Only reset the flag after the
GONE transition has completed.

Fixes: 338603686
Test: atest KeyguardRootViewModelTest
Flag: ACONFIG com.android.systemui.migrate_clocks_to_blueprint
TEAMFOOD

Change-Id: I59651b380fc149b44899f74ad123c04a4fdbcdb3