[RRS] Send event to AccessibilityManager when an unselect radio button is selected.

Change the screen resolution will cause re-layout the screen, so the focus will back to the first view. Before we actually set the screen
resolution, send an event to the AccessibilityManager and set what it
should say when the user selects the unselect option. Therefore TB will
say "selected" before the screen refreshes.

bug: 229352892
Test: Enable/disable Talkback and check RRS app behaivor. It should read
"selected" after user choose one un-selected option.

Change-Id: If14ed3685f85962d4e4b1d4961216c6ca5d5f0f8