Increase work_mem for gitlab.com CI database
The gitlab.com CI database (both replicas and primary) is using temp files. This indicates that we may be consistently spilling sorts to disk. We might want to increase the work_mem
setting to alleviate this and improve performance.
On CI we don't see the same [level of load as on main](https://gitlab.com/gitlab-com/gl-infra/production/-/issues/178920, but there is still room for improvement.
rate(pg_stat_database_temp_bytes{env="gprd", type="patroni-ci"}[15m])