WIP: Resolve "List Sentry Errors in GitLab"

What does this MR do?

This MR contains:

• Feature flag error_tracking
• Serve list of errors from Sentry
• Wait until https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23724 is merged 🔀

What are the relevant issue numbers?

#55178 (closed)

🍒 from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23770

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer

Closes #55178 (closed)

Based on !23724 (merged)