User-resize pip to normal bounds when (un)folding

If folding or unfolding makes the pip window size either larger
than maximum size or smaller than minimum size, then user-resize
to normal bounds.

Test: manually reproduced steps in the bug listed
Test: atest WMShellUnitTests:PipResizeGestureHandlerTest

Bug: 198679951
Bug: 198645990
Change-Id: I4a8c0a3a0fa75ab3d51d30e75bc85a53e4801086