Transfer coordinate into new Rect instead of in-place

Other parts of the animation rely on currentRectF to remain stable, therefore we shouldn't modify the RectF object in place.

Bug: 323628523
Flag: NONE
Test: Manual, i.e. verifying that widget close (and app close) animation animates correctly regardless of device orientation
Change-Id: I48e9ed047b956db654192eef39e5d94fbac53553