fix(usage): let the restricted story show the state it is named for

The harness kept the old guard when the page moved to rendering on the
block, so RestrictedButBackUnderTheLimit rendered nothing at all.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: talissoncosta

frontend/documentation/components/UsageDashboard.stories.tsx

@@ -141,7 +141,7 @@ const UsagePage: FC<HarnessProps> = ({
       // Nothing to refetch here; passed so FailedToLoad renders its button.
       onRetry={() => {}}
     >
-      {exceeded && (
+      {(exceeded || isRestricted) && (
         <OverLimitBanner
           over={exceeded}
           basis={basis}