There is no option for this, the user can always chooses to hide their email address.
https://developer.apple.com/documentation/authenticationservices/implementing_user_authentication_with_sign_in_with_appleIf the user is signed in at the system-level with their Apple ID, the sheet appears describing the Sign in with Apple feature, followed by another sheet allowing the user to edit the information in their account.
The user can edit their first and last name, choose another email address as their contact information, and hide their email address from the app.
If the user chooses to hide their email address from the app, Apple generates a proxy email address to forward email to the user’s private email address.