swarm-controller: fix test helper's forge::Client initializer

The stub-client helper in forge.rs built Client { api } after #4703
added a url field, breaking compilation of swarm-controller's test
target on main. Clone the URL the helper already builds for
Forgejo::new so it can also populate Client.url.

Closes #4709

swarm-controller/src/forge.rs

@@ -1492,8 +1492,8 @@ mod tests {
         let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
         let url = url::Url::parse(&format!("http://{}/", listener.local_addr().unwrap())).unwrap();
         tokio::spawn(async move { axum::serve(listener, app).await });
-        let api = Forgejo::new(Auth::Token("stub-token"), url).unwrap();
-        (Client { api }, seen)
+        let api = Forgejo::new(Auth::Token("stub-token"), url.clone()).unwrap();
+        (Client { api, url }, seen)
     }
 
     /// The `PATCH` [`Client::ensure_agent_user`] sent, if any.