Orgs sidebar shows loading indicator for User Admin

related to coder/internal#331

If a user is missing the User Admins permission but otherwise has access to an org, they can navigate to an orgs page directly and see the main content. But the Orgs sidebar will forever be stuck in a loading state

<img width="1521" alt="Image" src="https://github.com/user-attachments/assets/4f7fd5a2-ffd9-42bd-b1f7-452fbb9df00b" />