WIP: DRY up repository `archive` spec

What does this MR do?

This just DRYs up the spec for Repository#Archive by reusing the get_archive method. It also changes single quotes to double quotes according to our style guides.

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