fix: linting and go test

backend/chat/src/metrics/metrics.go

@@ -68,7 +68,7 @@ func ObserveRequestDuration(duration time.Duration) {
 func WrapRequestTiming(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		startedAt := time.Now()
-		defer ObserveRequestDuration(time.Since(startedAt))
+		defer func() { ObserveRequestDuration(time.Since(startedAt)) }()
 		next(w, r)
 	}
 }