[Magnifier-62] Deprecate constructor

The CL deprecates the old constructor for Magnifier instances in favor
of the usage of builder Magnifier#Builder.

Bug: 116116502
Test: atest CtsWidgetTestCases:android.widget.cts.MagnifierTest
Change-Id: I3daa9f066c77144e9d5c62bc666ecd37041f4bbb
3 files changed