On keycode confirmKey (ENTER/SPACE) on keyguard, show primaryBouncer

This CL also updates the PIN and Password primary bouncer
input views to act on confirmKey ACTION_UP instead of ACTION_DOWN.
This is to ensure that other consumers will not receive
the ACTION_UP when the view disappears after the bouncer transitions
away.

Fixes: 270883077
Test: atest KeyguardKeyEventInteractorTest
Test: atest SystemUIMicrobenchmark:android.platform.test.scenario.sysui.notification.NotificationRemoteInput
Change-Id: I1f36cf3a7e22942885320e7bc05eef6a058945ff