fix(fulfillment) Variants changed from managed inventory to unmanaged are now fulfillable (#14056)

* (fix) Variants changed from managed inventory to unmanaged are now fulfillable

* Changeset

* Update dull-donkeys-ring.md

packages/core/core-flows/src/order/workflows/mark-order-fulfillment-as-delivered.ts

@@ -168,8 +168,8 @@ function prepareRegisterDeliveryData({
         const iitem = iitems.find(
           (i) => i.inventory.id === fitem.inventory_item_id
         )
-
-        quantity = MathBN.div(quantity, iitem!.required_quantity)
+        if(iitem)
+          quantity = MathBN.div(quantity, iitem.required_quantity)
       }
 
       return {