Allow PipContentOverlay visible for only 1 time

It appears to be an existing flaky assertion for PipContentOverlay. And
it should be legit and depends on the speed of the transition.

Bug: 265998256
Test: atest WMShellFlickerTests:EnterPipOnUserLeaveHintTest
Change-Id: I7879dd3e5292c6cc28bdd5e57710548eb5697f82
1 file changed