Prevent PiP and Bubble from overlapping.

This is a partial fix for b/222229398.

Recall: http://recall/clips/ebd8432c-6b03-4ceb-9ca1-1b18dad59b64

Bug: 222229398
Test: atest WMShellFlickerTestsPip2
Test: atest WMShellUnitTests
Test: Launch a PiP window and a bubble. Move the PiP window on top of
the bubble and verify the bubble moves out of the way.
Flag: EXEMPT bug fix

Change-Id: I2136de50350cefa8f0aae216c4d6a63f7f8df1cb