Generate email confirmation secret from tagged_secret (#4480)

src/pretix/base/services/mail.py

@@ -301,7 +301,7 @@ def mail(email: Union[str, Sequence[str]], subject: str, template: Union[str, La
                         order.event, 'presale:event.order.open', kwargs={
                             'order': order.code,
                             'secret': order.secret,
-                            'hash': order.email_confirm_hash()
+                            'hash': order.email_confirm_secret()
                         }
                     )
                 )