Perform hit test before allowing the pointer icon to be set

Since we do not want to allow apps that are not receiving a pointer to
change the pointer icon, do a hit test before setting the pointer icon,
and drop any requests from windows that are not receiving the pointer.

Bug: 293587049
Bug: 266579357
Test: manual with mouse, ensure app can set the pointer icon
Change-Id: Ica0e7a19f4ed4e127b0e51a7a9b1f638dc056a72