fix: MerchantOrderDispatch 从 merchant_ops.models 导入

merchant_ops/helpers.py

@@ -3,7 +3,8 @@ import logging
 
 from backend.utils import pick_order_id
 from merchant_ops.services.authz import StaffAuthError, member_has_perm
-from orders.models import MerchantOrderExt, MerchantOrderDispatch
+from merchant_ops.models import MerchantOrderDispatch
+from orders.models import MerchantOrderExt
 from users.business_models import User
 
 logger = logging.getLogger(__name__)