Add method to set SkipScreenshot flag on cursorcontroller sprites

Add a methods to be able to set ISurfaceComposerClient::eSkipScreenshot
flag on MouseCursorController. This will be used to hide mouse and
stylus pointers on mirrored displays when a privacy sensitive window is
present on source display.

Test: manual test & atest PointerControllerTest
Bug: 325252005
Change-Id: Ide428e8daf96a1d919adb9d6374a9ea738f87cc5