ACQE-8329: Cart updates with multiple product changes and admin cart management

- Created data entity

Author: glo74186

app/code/Magento/Checkout/Test/Mftf/Data/CheckoutMessageData.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+-->
+<entities xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:noNamespaceSchemaLocation="urn:magento:mftf:DataGenerator/etc/dataProfileSchema.xsd">
+    <entity name="CheckoutOutOfStockMessageData">
+        <data key="headerMessage">Some of the products are out of stock.</data>
+        <data key="productItemMessage">There are no source items with the in stock status</data>
+    </entity>
+</entities>