citra_qt: Update the multiplayer dialogs when game list is repopulated

The multiplayer state object and dialogs hold a (modified) game list model, but it isn't updated when the actual game list changes. This updates the multiplayer dialogs with the new game list when it got repopulated.

src/citra_qt/game_list.cpp

@@ -421,6 +421,8 @@ void GameList::DonePopulating(QStringList watch_list) {
     if (childrenTotal > 0) {
         search_field->setFocus();
     }
+
+    emit PopulatingCompleted();
 }
 
 void GameList::PopupContextMenu(const QPoint& menu_location) {