SAMLIdentity GraphQL object now supports `read` scope

GitHub Enterprise Cloud administrators may need to review external identity information via the GraphQL API. Historically, this has required a token with the admin:org or admin:enterprise scope. We've taken a "least privilege" mindset in reviewing this flow and have now made this information available via the read:enterprise and read:org scopes for enterprise owner and organization owner actors.

For more information, see the GraphQL API documentation for Enterprise and Organization SAMLIdentity objects.