Fix "Fatal Error in PagesSettingsController.AddSideMenu(); Missing argument 1 for PagesSettingsController::AddSideMenu()"

Fixed the "Fatal Error in PagesSettingsController.AddSideMenu(); Missing
argument 1 for PagesSettingsController::AddSideMenu()" bonk that shows
up if error reporting is set to "E_ALL & ~E_NOTICE & ~E_STRICT" in PHP.