MC-31586: Customer address is duplicated after setBillingAddressOnCart GraphQL mutation.

- review fixes

Author: Prabhu Ram

app/code/Magento/QuoteGraphQl/Model/Cart/SetBillingAddressOnCart.php

@@ -118,6 +118,7 @@ private function createBillingAddress(
 
             $customerId = $context->getUserId();
             // need to save address only for registered user and if save_in_address_book = true
+            // and address is not same as shipping
             if (0 !== $customerId
                 && isset($addressInput['save_in_address_book'])
                 && (bool)$addressInput['save_in_address_book'] && !$sameAsShipping

dev/tests/api-functional/testsuite/Magento/GraphQl/Quote/Customer/SetBillingAddressOnCartTest.php

@@ -894,7 +894,7 @@ public function testSetBillingAddressAndPlaceOrder()
             street: ["test street 1", "test street 2"]
             city: "test city"
             region: "AZ"
-            postcode: "887766"
+            postcode: "88776"
             country_code: "US"
             telephone: "88776655"
             save_in_address_book: true