Reuse test setup for Secure E2E report tests

What does this MR do?

Addresses run length in Secure E2E report tests by running expensive test setup only once for these read-only tests.

Part 1 of https://gitlab.com/gitlab-org/quality/team-tasks/issues/266.

Screenshots

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