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/multiplayer/host_room.h

@@ -38,6 +38,11 @@ public:
                             std::shared_ptr<Core::AnnounceMultiplayerSession> session);
     ~HostRoomWindow();
 
+    /**
+     * Updates the dialog with a new game list model.
+     * This model should be the original model of the game list.
+     */
+    void UpdateGameList(QStandardItemModel* list);
     void RetranslateUi();
 
 private: