Add option to disable Login and Error pages when using Delivery API

[bjarnef]

Currently in backoffice when configuring protected content the login and error pages are mandatory.

However in a headless setup using Delivery API, we don't use these and these are configured using LoginRedirectUrls and LogoutRedirectUrls instead.
https://docs.umbraco.com/umbraco-cms/reference/content-delivery-api/protected-content-in-the-delivery-api

Could these properties be hidden and not validated, when DeliveryApi > MemberAuthorization > AuthorizationCodeFlow > Enabled is set to true? Or another settings property? Or a notification to change this?