Add enable_auto_assign_gitlab_duo_pro_seats namespace setting
What does this MR do and why?
In this MR, we:
- Add
auto_assign_gitlab_duo_pro_seats
feature flag (resolving https://gitlab.com/gitlab-org/gitlab/-/issues/457489+) - Add
enable_auto_assign_gitlab_duo_pro_seats
namespace setting (resolving https://gitlab.com/gitlab-org/gitlab/-/issues/458093+)
How to set up and validate locally
Specs are enough