Show HUN when bubbles cannot show notification

When Bubbles cannot show a bubble notification, currently this is when
the IME is visible and bubbles are showing in the bar, show it as a HUN

before: http://recall/-/bJtug1HhvXkkeA4MQvIaiP/gI3Rp68E5HPdPZ9i8Izbxw
after: http://recall/-/bJtug1HhvXkkeA4MQvIaiP/fdvIzvlOTqOTVBDwIQyo3r

Flag: com.android.wm.shell.enable_bubble_bar
Fixes: 340532785
Test: atest NotificationInterruptStateProviderImplTest
Test: atest VisualInterruptionDecisionProviderImplTest
Test: manual with the visual interruption refactor flag on and off
Change-Id: Ib75f30cce94e0e7b846a58dfaccac9c2369a366f