Notify interaction finalized when users are changing the seekbar progress without touching

With accessibility services, users are able to change the seekbar
progress without touching the it. In this case, we would like to notify
the interaction with seekbar has finished and set the font size.

Bug: 379216747
Test: atest FontScalingDialogDelegateTest
Test: atest SeekBaeWithIconButtonsViewTest
Test: atest WindowMagnificationSettingsTest
Test: Manually. Add videos to the bug
Flag: EXEMPT bugfix
Change-Id: Ibabb2c70ed5df82cc2ed4057ad7264f47c5e17bc