Don't scroll to position when undoing a deletion.

This seems to cause an issue where onSwipe is not being called anymore
afterwards. Steps to reproduce:
1. Delete a message
2. Scroll a little bit down
3. Undo delete
4. Try delete again
-> Swiping works, but callback is not being called.

app/src/main/java/com/github/gotify/messages/MessagesActivity.java

@@ -384,7 +384,6 @@ public class MessagesActivity extends AppCompatActivity
                             ? positionPair.getAllPosition()
                             : positionPair.getAppPosition();
             adapter.notifyItemInserted(insertPosition);
-            messagesView.smoothScrollToPosition(insertPosition);
         }
     }