fix: added a check to avoid double counting (#6925)

Due to how we handle redirects of embedded proxy, we ended up counting
the same request twice. This PR adds a boolean to res.locals which we
then check if set to avoid double counting.

src/lib/middleware/response-time-metrics.ts

@@ -70,7 +70,9 @@ export function responseTimeMetrics(
             time,
             appName,
         };
-
-        eventBus.emit(REQUEST_TIME, timingInfo);
+        if (!res.locals.responseTimeEmitted) {
+            res.locals.responseTimeEmitted = true;
+            eventBus.emit(REQUEST_TIME, timingInfo);
+        }
     });
 }