Avoid duplicated crop in PipAnimationController

The work around was added for b/178242567 to fix the black bar issue
when entering PiP in button navigation mode without valid source rect
hint, back in Android S.

This is no longer required, verified by local testing, w/wo source rect
hint. See the videos for reference.

Video: http://recall/-/aaaaaabFQoRHlzixHdtY/bXhAHpNcsmaRTPyrBBwJtN
Video: http://recall/-/aaaaaabFQoRHlzixHdtY/fZyEUvZqlH04EQxAM8k9YC
Bug: 333894859
Test: manually, make sure no regressions to b/178242567
Test: atest FlickerTestsOther#SecondaryActivityEnterPipTest
Change-Id: Iac030e59ec7bb88255b10255e0bce5ceea24a447