Dismiss the keyguard through #notifyKeyguardAuthentiated

In case a pending dismiss action exists when dreaming.

Test: manually launch an intent from dreaming and authenticate
through the alternate bouncer => see intent gets triggered
after authentication
Test: atest KeyguardViewMediatorTest
Fixes: 277284836

Change-Id: I9120460ad945caf015ea1b678d2a6e41103d42c7