Add UI feedback for comment deletion

Signed-off-by: Julius Härtl <jus@bitgrid.net>

js/controller/ActivityController.js

@@ -245,12 +245,10 @@ class ActivityController {
 	deleteComment(item) {
 		item.commentModel.destroy();
 		item.deleted = true;
+		item.commentModel = undefined;
+		item.message = t('deck', 'The comment has been deleted');
 	}
 
-	getCommentDetails() {}
-
-
-
 	getData(id) {
 		return this.activityservice.getData(this.type, id);
 	}