MC-19746: The shipping address contains null values when there's no shipping address set on a cart

- fix variable initialization

Author: cpartica

app/code/Magento/QuoteGraphQl/Model/Resolver/ShippingAddresses.php

@@ -56,7 +56,8 @@ public function resolve(Field $field, $context, ResolveInfo $info, array $value
 
         $shippingAddresses = $cart->getAllShippingAddresses();
 
-        if (count($shippingAddresses)) {
+        $addressesData = [];
+        if (!empty($shippingAddresses)) {
             foreach ($shippingAddresses as $shippingAddress) {
                 $address = $this->extractQuoteAddressData->execute($shippingAddress);