Drop tmp_index_ci_job_artifacts_on_id_expire_at_file_type_trace

Ref: #368979 (closed)

What does this MR do and why?

Following up !124071 (merged) where we removed successfully this index on gitlab.com.

This MR drops the index for self-managed users as it's no longer being used according to Thanos.

Screenshots or screen recordings

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.