Use code generated by qtwaylandscanner to send xdg-exported handle

This was overlooked during the port to the new approach.

src/wayland/xdgforeign_v2_interface.cpp

@@ -81,7 +81,7 @@ void XdgExporterV2Interface::zxdg_exporter_v2_export_toplevel(Resource *resource
     });
 
     m_exportedSurfaces[handle] = exported;
-    zxdg_exported_v2_send_handle(exportedResource, handle.toUtf8().constData());
+    exported->send_handle(handle);
 }
 
 XdgImporterV2Interface::XdgImporterV2Interface(Display *display, XdgForeignV2Interface *foreign)

src/wayland/xdgforeign_v2_interface_p.h

@@ -69,7 +69,7 @@ private:
     QHash<XdgImportedV2Interface *, SurfaceInterface *> m_children; //parent->child hash
 };
 
-class XdgExportedV2Interface : public QObject, QtWaylandServer::zxdg_exported_v2
+class XdgExportedV2Interface : public QObject, public QtWaylandServer::zxdg_exported_v2
 {
     Q_OBJECT