Qt: Add game list excluded folders as well as files

Backport of https://github.com/PCSX2/pcsx2/pull/9730

src/duckstation-qt/setupwizarddialog.h

@@ -38,6 +38,7 @@ private Q_SLOTS:
   void onDirectoryListContextMenuRequested(const QPoint& point);
   void onAddSearchDirectoryButtonClicked();
   void onRemoveSearchDirectoryButtonClicked();
+  void onSearchDirectoryListSelectionChanged();
   void refreshDirectoryList();
   void resizeDirectoryListColumns();