Fix back presses dismissing bubbles when IME is up

If bubbles is expanded & shade is not use the virtual display id of the
expanded activity view (if it's valid, otherwise do whats normal).

Test: manual  1) have expanded bubble with IME up
              2) hit back button
              => note that the IME goes away but the bubble remains

              1) have expanded bubble up
              2) pull down shade
              3) hit back button
              => shade goes away

              Do above with gesture nav turned on & do back gesture

Test: atest KeyButtonViewTest
Fixes: 122535136
Change-Id: Iabaace66cfb4d3d80b1a3a3c7b0773deb48fbcaa