Clear the ViewTranslationResponse on finishing UiTranslation.

Stored state should be cleared here.

This fixes a bug where the views cannot be re-translated after
UiTranslationManager#finishTranslation was called. Some of the state was
cleared, so the translations cannot be re-shown. And that state cannot
be recreated because we find the same ViewTranslationResponse stored and
do not recreate the other state.

Fix: 189892928
Test: manual - translate an app, go to the home screen (triggers
 finish), go back to the app and re-translate
Test: atest CtsTranslationTestCases
Change-Id: Ic81fbce7ee09eb72352071c8bdd94a2731826009