If bubble bar is collapsing, hide the IME

We do this in stackview, should also do it for layerview.

Flag: com.android.wm.shell.enable_bubble_bar
Test: manual - expand a bubble, show the IME, lock the device, unlock
               the device
             => observe that the IME is not still on screen
Fixes: 353899205
Change-Id: Ie3bf633e8f2428a509110bb2ea073eaffbaa7094