Fix issue where keyboard would not be dismissed

When swiping down from the top of the screen to dismiss the bouncer,
the input field should hide the keyboard, otherwise it would get stuck
on the lock screen.

Test: manual
Test: atest KeyguardHostViewTest
Test: atest KeyguardBouncerTest
Fixes: 154245193
Fixes: 152882608
Change-Id: I99ee2cff85df1ab0b6544e9b5b472e105fca7b72