in https://pub.dev/documentation/apple_sign_in/latest/apple_id_credential/AppleIdCredential-class.htmlthe "user" field response on a successful auth with Sign in w/ Apple is the unique user identifier, is this only returned when using the iOS SDK? i noticed "user" in https://developer.apple.com/documentation/signinwithapplejs/configuring_your_webpage_for_sign_in_with_apple is a JSON object with fullName and email. How would we get access to the apple unique ID via the JS SDK or REST API?Thanks.