Quarantine flaky test

What does this MR do?

Quarantines a flaky test `add_deploy_token_spec.rb` that failed multiple times in master, however, passes on some occasions. More investigation required.

See #213222 (closed) and gitlab-org/quality/pipeline-triage#23 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content