[Magnifier-53] Add API around outofbounds behavior

The CL adds a public API to enable customizing magnifier's behavior when
the coordinates passed to #show would position the magnifier outside the
main application window.

Bug: 72211470
Test: manual testing
Test: atest CtsWidgetTestCases:android.widget.cts.MagnifierTest
Change-Id: I9de26e446354d0ad987a4509089fbec4ee5ef7d3