Prepare async index for pipeline_id_convert_to_bigint

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/127471



Merged-by: Adam Hegyi <ahegyi@gitlab.com>
Approved-by: Adam Hegyi <ahegyi@gitlab.com>
Reviewed-by: charlie ablett <cablett@gitlab.com>
Reviewed-by: Tianwen Chen <tchen@gitlab.com>
Co-authored-by: Tianwen Chen <tchen@gitlab.com>