Allow auditor to read project MR analytics

Resolves #357336 (closed)

Allows users with auditor role to view project Merge request Analytics.

Steps to validate

1. Follow documentation to create an Auditor user
2. Log in as an Auditor user
3. Navigate to a project that your user is not a member of
4. You should see Analytics > Merge request in left nav at the project level

Screenshot

User @devgo is not a member of the project, but as an Auditor can see the Merge request Analytics: