Not to show intermediate screen to the user when dismissing split screen

During dismissing split screen mode, the logic may perform some surface
operations. e.g., setWindowCrop and hide. If we clear the crop of an app
stack first and then hide the app a few milliseconds later, the user may
see the screen flash.

This CL uses inSurfaceTransaction to ensure that there won't be any
intermediate transactions while setting windowing mode.

Fix: 79686616
Test: atest WindowManagerSmokeTest
Change-Id: Ie35c3422dd0c49b5145a6b80f0b78f23e27a11a1