Un-quarantine export project e2e test on staging

What does this MR do?

Un quarantines export project e2e test on staging

Related issue: #296212 (closed)

Related KR: gitlab-com/www-gitlab-com#10702 (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