Adding AAD B2C limitation on custom roles

Hi!
Azure AD B2C currently does not support Azure AD custom roles.
However, this information is not explicitly stated in the documentation, which causes ambiguities.
Hence, this proposal.
Thanks!

Author: LucasLeitao-MSFT

articles/active-directory-b2c/roles-resource-access-control.md

@@ -26,7 +26,7 @@ When planning your access control strategy, it's best to assign users the least
 |[Company branding](customize-ui.md#configure-company-branding)| Customize your user flow pages.| [Global Administrator](../active-directory/roles/permissions-reference.md#global-administrator)|
 |[User attributes](user-flow-custom-attributes.md)| Add or delete custom attributes available to all user flows.| [External ID User Flow Attribute Administrator](../active-directory/roles/permissions-reference.md#external-id-user-flow-attribute-administrator)|
 |Manage users| Manage [consumer accounts](manage-users-portal.md) and administrative accounts as described in this article.| [User Administrator](../active-directory/roles/permissions-reference.md#user-administrator)|
-|Roles and administrators| Manage role assignments in Azure AD B2C directory. Create and manage groups that can be assigned to Azure AD B2C roles. |[Global Administrator](../active-directory/roles/permissions-reference.md#global-administrator), [Privileged Role Administrator](../active-directory/roles/permissions-reference.md#privileged-role-administrator)|
+|Roles and administrators| Manage role assignments in Azure AD B2C directory. Create and manage groups that can be assigned to Azure AD B2C roles. Note that Azure AD custom roles's feature is currently not available for Azure AD B2C directories. |[Global Administrator](../active-directory/roles/permissions-reference.md#global-administrator), [Privileged Role Administrator](../active-directory/roles/permissions-reference.md#privileged-role-administrator)|
 |[User flows](user-flow-overview.md)|For quick configuration and enablement of common identity tasks, like sign-up, sign-in, and profile editing.| [External ID User Flow Administrator](../active-directory/roles/permissions-reference.md#external-id-user-flow-administrator)|
 |[Custom policies](user-flow-overview.md)| Create, read, update, and delete all custom policies in Azure AD B2C.| [B2C IEF Policy Administrator](../active-directory/roles/permissions-reference.md#b2c-ief-policy-administrator)|
 |[Policy keys](policy-keys-overview.md)|Add and manage encryption keys for signing and validating tokens, client secrets, certificates, and passwords used in custom policies.|[B2C IEF Keyset Administrator](../active-directory/roles/permissions-reference.md#b2c-ief-keyset-administrator)|