[DOCS] SAML with Azure Active Directory using outdate API

This [page](https://www.elastic.co/guide/en/cloud/current/ec-securing-clusters-saml-azure.html) the last section for Configure SAML with Azure AD to access Kibana that discusses "Role Mapping" has an example that leverages an outdate API. Instead of `POST /_xpack/security/role_mapping/SAML_kibana`, the API should be `POST /_security/role_mapping/SAML_kibana`

This example could be made more complete by showing how to create a role against an Active Directory group rather than which I don't believe is a default returned from Azure AD into our Name field. By default, I believe its the user's principal, which based upon the example configurations above would be the users email address.

リンク先の SAML with Azure AD ドキュメントページを開き、最後の「Role Mapping」セクションを見つけます。古くなった role-mapping API の例を更新し、続いて周辺の Azure AD 設定を確認して、その例でユーザーの principal と Active Directory グループのどちらを使用すべきかを判断し、レンダリングされたドキュメントを検証します。

索引モデルが issue の本文から書いたものです。