CE port of "Add test for git http operations for SSO enforced SAML group"

What does this MR do?

Ports changes from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/13570

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content