graphQl: fixed multi shipping model

Author: vitaliyboyko

app/code/Magento/QuoteGraphQl/Model/Resolver/ShippingAddress/SetShippingAddressOnCart/MultiShipping/ShippingItemsMapper.php

@@ -14,7 +14,7 @@ class ShippingItemsMapper
 {
 
     /**
-     *  Converts shipping address input array into shipping items information array
+     * Converts shipping address input array into shipping items information array
      * Array structure:
      * array(
      *      $cartItemId => array(

app/code/Magento/QuoteGraphQl/etc/graphql/di.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0"?>
+<!--
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+-->
+<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
+    <virtualType name="multishippingPaymentSpecification" type="Magento\Payment\Model\Method\Specification\Composite">
+        <arguments>
+            <argument name="specifications" xsi:type="array">
+                <item name="enabled" xsi:type="string">Magento\Multishipping\Model\Payment\Method\Specification\Enabled</item>
+            </argument>
+        </arguments>
+    </virtualType>
+    <type name="Magento\Multishipping\Block\Checkout\Billing">
+        <arguments>
+            <argument name="paymentSpecification" xsi:type="object">multishippingPaymentSpecification</argument>
+        </arguments>
+    </type>
+    <type name="Magento\Multishipping\Model\Checkout\Type\Multishipping">
+        <arguments>
+            <argument name="paymentSpecification" xsi:type="object">multishippingPaymentSpecification</argument>
+        </arguments>
+    </type>
+</config>