Record direct Orbit enrollments on self-managed

What does this MR do and why?

Orbit is GA on self-managed and Dedicated, so turning it on there now records a direct enrollment instead of a beta one. Without this, re-enabling Orbit would bring the beta trial exemption back after the beta cleanup in !261194 (closed) removes it. GitLab.com is unchanged and stays gated by orbit_promo_access_gate.

Decided: no new flag or setting. This ships unconditionally in 19.6 off GitLab.com.

References

• Relates to https://gitlab.com/gitlab-org/orbit/knowledge-graph/-/work_items/1354
• Prerequisite for !261194 (closed)

How to set up and validate locally

1. Run bundle exec rspec ee/spec/workers/analytics/knowledge_graph/auto_index_worker_spec.rb ee/spec/requests/api/admin/knowledge_graph_spec.rb ee/spec/services/analytics/knowledge_graph/toggle_namespace_service_spec.rb

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist.

Agent context

• Off GitLab.com the billing account is the instance account; on GitLab.com it is the group account. Each now defines record_without_trial: direct for the instance account, beta for the group account.
• Per-group turn-on and the admin API both go through that path; auto-index writes direct directly.
• The trial flow (orbit_trial) and promo gate branches are untouched, so their behaviour is the same.
• record_direct converts an existing beta row to direct, so beta rows on self-managed convert when re-enabled.
• The beta enum value, beta? checks and the development seed are left alone.
• Specs updated for auto-index and the admin API, and a self-managed toggle spec added. Related Orbit specs pass.