Reload stable object to prevent erase artifacts with old state (Ver 2)

What does this MR do?

• CE: Here
• EE: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4844

This fixes, when UpdatePagesService tried to erase artifacts, it raises an exception as Errno::ENOENT: No such file or directory, because it tries to erase it with old state.

For example, even if BackgroundMoveWorker updated file_store to 2 of ci_job_artifacts asynchronously, still UpdatePagesService reffers it as file_store is nil.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug
• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/43641