magento/graphql-ce#977: [Test coverage] Cover exceptions in AssignShippingAddressToCart, AssignBillingAddressToCart

Merge remote-tracking branch 'origin/2.3-develop' into 977-address-to-customer

# Conflicts:
#	dev/tests/api-functional/testsuite/Magento/GraphQl/Quote/Customer/SetBillingAddressOnCartTest.php
#	dev/tests/api-functional/testsuite/Magento/GraphQl/Quote/Customer/SetShippingAddressOnCartTest.php

Author: atwixfirster

README.md

@@ -64,7 +64,7 @@ Please see LICENSE_EE.txt for the full text of the MEE License or visit https://
 
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