Auth override email of ldap plugin

[bammab]

Hi,

when using the ldap auth plugin with "manage_user": True against an AD, the email of the user will be read, but overriden by "USER@example.com".
I have temporary fixed this behavior with this code (added lines marked with a plus):

    def get_or_register_user(self, user):
         db = self.db
         # if we have an sso_id we use it to id the user
         if user.get("sso_id"):
             keyid = "sso_id"
             row = (
                 db(db.auth_user.sso_id == user["sso_id"]).select(limitby=(0, 1)).first()
             )
             # the sso source is always more authoritative so update the record
             if row:
+                if row.email and "email" in user and user.get("email").endswith("example.com"):
+                    del user["email"]
                 row.update_record(**user)
                 # pass the full user
                 user = row.as_dict()

I don't know if this could be side effacts or break something.