Fix hard dragging from the edge of the screen

When the mirror window is at the edge of the screen,
it is hard to drag it from the side closed to the edge
because the motion events will be cancelled due to edge-back
gesture detection.

To fix it, we inovke setSystemGestureExclusionRects when the
window layout is changed.

Bug: 189936169
Test: atest WindowMagnificationControllerTest
      manually test
Change-Id: I775ce8d6d69aeb3fe1d4433c4e1667bd478b26b3