style: format metrics.py

app/metrics.py

@@ -143,9 +143,7 @@ def record_dedup(outcome: str) -> None:
         _dedup_counter.labels(outcome=outcome).inc()
 
 
-def observe_request_duration(
+def observe_request_duration(method: str, endpoint: str, status: int, duration: float) -> None:
-    method: str, endpoint: str, status: int, duration: float
-) -> None:
     """Record request duration.
 
     Args: