Fix auditor permission in group VSA

What does this MR do and why?

This MR fixes the HTTP 403 errors on the group value stream analytics page when the current user is auditor.

How to set up and validate locally

1. Ensure that you're on premium or ultimate plan.
2. Create an auditor user.
3. Log in
4. Open the dev console and see the network requests.
5. Go to a group > Analytics > Value Stream
6. The page should load and you shouldn't see 403 errors.

Note: auditor user doesn't have the right to create/edit value streams.

Related to #464469 (closed)