🗑️(backend) remove useless methods on User

While removing analytics code in 15e922f, I forgot to remove
related code in the User model, used nowwhere else. Oopsie.
Fixed it!

src/backend/core/models.py

@@ -207,13 +207,6 @@ class User(AbstractBaseUser, BaseModel, auth_models.PermissionsMixin):
         """
         return []
 
-    @property
-    def email_anonymized(self):
-        """Anonymize the email address by replacing the local part with asterisks."""
-        if not self.email:
-            return ""
-        return f"***@{self.email.split('@')[1]}"
-
 
 def get_resource_roles(resource: models.Model, user: User) -> List[str]:
     """