fix(sandbox-provider): prevent permission hint flash on page load

Use strict equality check to only show no-permission message when
isCurrentWorkspaceOwner is explicitly false, not undefined.

web/app/components/header/account-setting/sandbox-provider-page/index.tsx

@@ -73,7 +73,7 @@ const SandboxProviderPage = () => {
         </div>
       )}
 
-      {!isCurrentWorkspaceOwner && (
+      {isCurrentWorkspaceOwner === false && (
         <div className="system-xs-regular text-text-tertiary">
           {t('sandboxProvider.noPermission', { ns: 'common' })}
         </div>