Merge branch 'MC-18402' of github.com:magento-honey-badgers/magento2ce into MC-18402

Author: dthampy

app/code/Magento/SalesRule/etc/extension_attributes.xml

@@ -7,6 +7,6 @@
 -->
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
     <extension_attributes for="Magento\Quote\Api\Data\CartItemInterface">
-        <attribute code="discounts" type="array" />
+        <attribute code="discounts" type="string" />
     </extension_attributes>
-</config>
+</config>