Add avoidInlineStyle to mjml demo

demo-mjml.html

@@ -164,6 +164,7 @@
       var editor = grapesjs.init({
         clearOnRender: true,
         height: '100%',
+        avoidInlineStyle: false,
         storageManager: {id: 'gjs-mjml-'},
         //storageManager:{ autoload: 0 },
         assetManager: {