Fix opening the Spotify config dialog from the context menu.

src/radio/spotifyservice.cpp

@@ -411,3 +411,8 @@ void SpotifyService::ImageLoaded(const QString& id, const QImage& image) {
   qLog(Debug) << "Image loaded:" << id;
   emit ImageLoaded(QUrl("spotify://image/" + id), image);
 }
+
+void SpotifyService::ShowConfig() {
+  emit OpenSettingsAtPage(SettingsDialog::Page_Spotify);
+}
+

src/radio/spotifyservice.h

@@ -81,6 +81,8 @@ private slots:
   void OpenSearchTab();
   void DoSearch();
 
+  void ShowConfig();
+
 private:
   SpotifyServer* server_;
   SpotifyUrlHandler* url_handler_;