Don't throw notices in postDelete() if the deleted entity is malformed (required field empty).

modules/order/src/Entity/Order.php

@@ -107,6 +107,9 @@ class Order extends ContentEntityBase implements OrderInterface {
     // Delete the line items of a deleted order.
     $lineItems = [];
     foreach ($entities as $entity) {
+      if (empty($entity->line_items)) {
+        continue;
+      }
       foreach ($entity->line_items as $item) {
         $lineItems[$item->target_id] = $item->entity;
       }

modules/product/src/Entity/Product.php

@@ -186,6 +186,9 @@ class Product extends ContentEntityBase implements ProductInterface {
     // Delete the product variations of a deleted product.
     $variations = [];
     foreach ($entities as $entity) {
+      if (empty($entity->variations)) {
+        continue;
+      }
       foreach ($entity->variations as $item) {
         $variations[$item->target_id] = $item->entity;
       }