[Magnifier-55] Add API for content clamping

The CL adds API to customize the bounds relative to a view where the
magnifier content is allowed to be copied from.

Bug: 72211470
Test: manual testing
Test: atest CtsWidgetTestCases:android.widget.cts.MagnifierTest
Change-Id: I3016a34929acf029f5251d03812f17e4da4cb948