Tell the app that a smart reply was used even when it has been edited.

The existing API RemoteInput.Source covers two scenarios for responding
to message notifications:
1. A user uses the 'reply' button and enters a response freely.
2. A user clicks a smart reply which is used as the response.

Before this CL the platform would notify the app of scenario nr. 1 in
the case where we use tap-to-edit smart replies (replies that can be
edited before being sent). With this CL we instead log scenario nr. 2
(since a smart reply was clicked).

Bug: 123407240
Test: use a test-app to ensure that a response created using smart
replies + tap-to-edit logs the correct @Source.
Change-Id: I3dc8169a3c440af106c4f244b72ddf7c9e450203