AC-7058: Guest Checkout REST API Fix

Author: pawan-adobe-security

app/code/Magento/Quote/Model/QuoteAddressValidator.php

@@ -133,8 +133,9 @@ private function doValidateForGuestQuoteAddress(AddressInterface $address, CartI
     {
         //validate guest cart address
         if ($address->getId() !== null) {
+            $size = $cart->getAddressesCollection()->getSize();
             $old = $cart->getAddressesCollection()->getItemById($address->getId());
-            if ($old === null) {
+            if ($old === null && $size > 0) {
                 throw new NoSuchEntityException(
                     __('Invalid quote address id %1', $address->getId())
                 );