Fix Transparent bounds from client layout

If the client uses a layout with LayoutParams.WRAP_CONTENT it
might happen that the requeste size for the translucent activity
is smaller than the one provided by core through Configuration.
In that case we need to adjust the bounds we use for cropping
when applying rounded corners.

Fix: 278525445
Test: Run atest WmTests:LetterboxUiControllerTest

Change-Id: Ife63ab94c7fb7dd27d3d6c773806d9c49cd8eae8