Allow Watch Unlock to exit back to Device Unlock settings.

Seeking to imitate the behavior from fingerprint and face unlock. In GMS
Core we will control when to send the RESULT_TIMEOUT resultCode, but we
should generally exit all the way out to Device Unlock, where there is a
passcode entry requirement, when we swipe away from Watch Unlock's
settings.

Flag: com.android.settings.flags.active_unlock_finish_parent
Test: Manually
Bug: 343576960

Change-Id: Ia9a1564295a44ab6925ea9fceebf92f437e03731