Update DisableInventoryBackOrdersTest.xml

Author: manjusha729

app/code/Magento/CatalogInventory/Test/Mftf/Test/DisableInventoryBackOrdersTest.xml

@@ -19,6 +19,7 @@
         </annotations>
 
         <before>
+            <magentoCLI command="config:set {{EnableFlatRateConfigData.path}} {{EnableFlatRateConfigData.value}}" stepKey="enableFlatRate"/>
             <!-- Enable Back Orders-->
             <magentoCLI command="config:set cataloginventory/item_options/backorders 1" stepKey="EnableBackorders"/>
             <!--Create Category-->