Interrupt bubble animation when IME is visible

When the IME becomes visible, interrupt the bubble animation if it's
running. This ensures that the flyout doesn't show over the IME and
is more consistent with the behavior of bubble notification when the
IME is visible.

Flag: com.android.wm.shell.enable_bubble_bar
Fixes: 378404363
Test: atest BubbleBarViewAnimatorTest
Test: manual
       - launch app
       - send bubble
       - while bubble is animating launch IME
       - observe flyout not visible over IME
Change-Id: I28390982bb41d8cc9b494395418728ff5fb373b6