Add test for instance audit logs

What does this MR do?

Adds test for instance audit logs

This is the last MR required to close gitlab-org/quality/testcases#195 (closed)

Closes gitlab-org/quality/testcases#195 (closed)

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