fix: cascade delete for deal products and product services

modules/fulfillment_base/models/deal_product.py

@@ -27,6 +27,7 @@ class DealProduct(BaseModel):
     product_services: Mapped[list["DealProductService"]] = relationship(
         back_populates="deal_product",
         primaryjoin="and_(DealProduct.deal_id==DealProductService.deal_id, DealProduct.product_id==DealProductService.product_id)",
+        cascade="all, delete-orphan",
     )
 
 
@@ -56,5 +57,6 @@ class DealProductService(BaseModel, PriceMixin):
                 "fulfillment_base_deal_products.deal_id",
                 "fulfillment_base_deal_products.product_id",
             ],
+            ondelete="CASCADE",
         ),
     )