refactor(metrics): simplify response building with unwrap_or_else

- Replace explicit match statement with unwrap_or_else for cleaner error handling
- Maintain same error logging behavior when response building fails
- Reduce code complexity and improve readability
- Keep identical fallback response creation on builder errors

metrics.rs

@@ -575,18 +575,14 @@ fn json_response(status: u16, body: &str) -> Response<Full<Bytes>> {
 }
 
 fn text_response(status: u16, content_type: &str, body: String) -> Response<Full<Bytes>> {
-    match Response::builder()
+    Response::builder()
         .status(status)
         .header("Content-Type", content_type)
         .header("Connection", "close")
-        .body(Full::new(Bytes::from(body)))
-    {
-        Ok(response) => response,
-        Err(err) => {
-            tracing::error!(error = %err, "failed to build text response");
-            Response::new(Full::new(Bytes::from_static(b"response build failed")))
-        }
-    }
+        .body(Full::new(Bytes::from(body))).unwrap_or_else(|err| {
+        tracing::error!(error = %err, "failed to build text response");
+        Response::new(Full::new(Bytes::from_static(b"response build failed")))
+    })
 }
 
 async fn handle_request(req: Request<Incoming>) -> Result<Response<Full<Bytes>>, Infallible> {