(Azure CXP) Adds a missing step

resolves MicrosoftDocs/azure-docs#48360

Author: mikeurnun

articles/azure-functions/durable/durable-functions-create-portal.md

@@ -52,6 +52,8 @@ If you are creating JavaScript Durable Functions, you'll need to install the [`d
 4. Once your `package.json` is uploaded, run the `npm install` command from the Kudu Remote Execution Console.
 
    ![Kudu run npm install](./media/durable-functions-create-portal/kudu-npm-install.png)
+   
+5. Lastly, (enable compatibility mode)[https://docs.microsoft.com/en-us/azure/azure-functions/durable/quickstart-js-vscode#enable-compatibility-mode-1] by adding an app setting `FUNCTIONS_V2_COMPATIBILITY_MODE` with value of `true`.
 
 ## Create an orchestrator function