Validate hotspot when loading PointerIcon from resource

Currently PointerIcon.load and PointerIcon.getSystemIcon do not
check if the hotspot position is within the bounds of the underlying
bitmap. The check is performed only in PointerIcon.createFromParcel
which is called in the system server process and the resulting
exception might be hard to trace to the root cause.

Bug: 70862454
Test: android.widget.cts.PointerIconTest
Change-Id: I7f19cc9fc60b7bf72ad53403c203087201a5810c