Unmasked SSN for one provider with an active membership in the
organization. Returns a 404 if the provider is not in the organization.

Accepts an organization API key, or an Enterprise API key with the
X-Medallion-Organization-Id header identifying one of the enterprise's
linked organizations.

Beta: this endpoint is part of a limited beta launch and is not yet
enabled for all organizations. Reach out to your Medallion contact if
you'd like to use it. Organizations outside the beta receive a 403.