Fix cropped bubble flyout when animating in app

When animating the bubble bar in an app with a stashed handle,
the flyout might not be displayed entirely.

Fix the calculation of the amount of space needed to fully display
the bubble bar and flyout views.

Flag: com.android.wm.shell.enable_bubble_bar
Fixes: 382513856
Test: manual
       - remove all bubbles
       - launch app
       - send a bubble with a 2-line message
       - observe flyout is fully visible
Change-Id: I7953cb7f619f2c00b04bb4cb08c57a8195ff79fe