Only run timeago loops after rendering timeago components

What does this MR do?

Guarantees we only run the timeago loops after we render the table rows.

We were running the function at the same time we made the request to the API which caused some errors in the browser and in some rspec tests (https://gitlab.com/gitlab-org/gitlab-ce/builds/10536121).

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #28247 (closed)