Notify Content Capture when deselected

Notify Content Capture with the text changed event when deselected.

Bug: 184311217
Test: manual
 1.long press trigger selection, event is sent.
 2.drag selection indicators, send event after the drag is done.
 3.deselecting, event is sent.
Test: atest CtsContentCaptureServiceTestCases
Change-Id: I3d05b8e798bfb5b213817b36f163aab0a688bdf4