add relay in --config https://github.com/rustdesk/rustdesk/discussions/7118

src/core_main.rs

@@ -348,6 +348,7 @@ pub fn core_main() -> Option<Vec<String>> {
                                 lic.host,
                             );
                             crate::ui_interface::set_option("api-server".into(), lic.api);
+                            crate::ui_interface::set_option("relay-server".into(), lic.relay);
                         }
                     }
                 } else {