Move PiP window back to its previous location after IME is dismissed.

Recall: http://recall/clips/16488e9a-666c-4d2f-8d6f-b330f8a7ac45

Test: atest WMShellFlickerTestsPip2
Test: Show IME and dismiss IME. Verify that PiP returns to the location
before IME is shown.
Test: Manually move/resize PiP window while IME is expanded and verify
that when IME is collapsed, the PiP window doesn't move/resize.
Bug: 348693761
Flag: EXEMPT bug fix

Change-Id: I125f8231aa80a0f869ee3120f7821eaef9ac6951