Merge branch '397000-sync-unique-index' into 'master'

Prepare async indexes and fks for ci_pipelines.id_convert_to_bigint

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/148034



Merged-by: Tianwen Chen <tchen@gitlab.com>
Approved-by: Marius Bobin <mbobin@gitlab.com>
Reviewed-by: Max Orefice <morefice@gitlab.com>
Reviewed-by: Tianwen Chen <tchen@gitlab.com>