set email_unique on save

Author: mifu67

src/sentry/users/models/user.py

@@ -229,6 +229,7 @@ def save(self, *args: Any, **kwargs: Any) -> None:
         with outbox_context(transaction.atomic(using=router.db_for_write(User))):
             if not self.username:
                 self.username = self.email
+            self.email_unique = self.email
             result = super().save(*args, **kwargs)
             for outbox in self.outboxes_for_update():
                 outbox.save()