Schedule ci_job_artifacts index for removal

Ref: #358042

What does this MR do and why?

This MR schedules index_ci_job_artifacts_on_expire_at_and_job_id for removal over the weekend.

It does not seem to be used according to Thanos in the last 2 months.

Screenshots or screen recordings

Database

• https://console.postgres.ai/gitlab/gitlab-production-ci/sessions/15639/commands/54175

List of relations
 Schema |                      Name                      | Type  |  Owner  |      Table       | Size  | Description 
--------+------------------------------------------------+-------+---------+------------------+-------+-------------
 public | index_ci_job_artifacts_on_expire_at_and_job_id | index | joe_292 | ci_job_artifacts | 79 GB | 
(1 row)

Impact

Reduced ci_job_artifacts size by 79 GB

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.