* 📫 refactor: Enhance OpenID email Fallback
* Updated email retrieval logic to use preferred_username or upn if email is not available.
* Adjusted logging and user data assignment to reflect the new email handling approach.
* Ensured email domain validation checks the correct email source.
* 🔄 refactor: Update Email Domain Validation Logic
* Modified `isEmailDomainAllowed` function to return true for falsy emails and missing domain restrictions.
* Added new test cases to cover scenarios with and without domain restrictions.
* Ensured proper validation when domain restrictions are present.