In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/32331 we
introduced the propagation of instance-level integrations to projects.

After adding the group_id column to the services table
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/38499 we can now
save integrations that belongs to a group
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/39959.

This propagate instance-level integration settings to groups.