Add minimum show time for the udfps bouncer.

So the udfps bouncer will show for a minimum of 200ms before
an outside touch will dismiss it and show the input
(pin/pattern/password) bouncer.

Also, make sure to intercept all touches when the udfps (alt) bouncer is
showing so that touches don't get propagated to the
ExpandableNotificationRow.

Test: atest UdfpsKeyguardViewControllerTest, NotificationShadeWindowViewTest.java
Fixes: 195612268
Change-Id: I737c9086d1debafb8c7024c035012602f4bdbee4