feat(webvitals): use flag in stored scores setting (#63254)

Add `starfish-browser-webvitals-use-backend-scores` check in
useStoredScoresSetting

Author: edwardgou-sentry

static/app/views/performance/browser/webVitals/utils/useStoredScoresSetting.tsx

@@ -1,14 +1,20 @@
 import {decodeScalar} from 'sentry/utils/queryString';
 import {useLocation} from 'sentry/utils/useLocation';
+import useOrganization from 'sentry/utils/useOrganization';
 import {USE_STORED_SCORES} from 'sentry/views/performance/browser/webVitals/settings';
 
 export function useStoredScoresSetting() {
   const location = useLocation();
   const {query} = location;
+  const organization = useOrganization();
 
   if (query.useStoredScores !== undefined) {
     return decodeScalar(query.useStoredScores) === 'true';
   }
 
+  if (organization.features.includes('starfish-browser-webvitals-use-backend-scores')) {
+    return true;
+  }
+
   return USE_STORED_SCORES;
 }