List non-admin advisors in the current advisory.

Intentionally NOT admin-gated. This reads through the RLS-scoped client, and the advisors SELECT policy ("Advisors can view advisors from their advisory") already exposes member advisor roster data to every advisor — so gating here would add no real protection (a member could query the advisors table directly) while breaking the maintainer add-member flow, which needs the roster to grant business access. The /settings/members mutation path (update_platform_role) is the one that is admin-gated via require_admin.