Fix EZP-22292 - eZDemo with content broken in ezpublish-community

#EZP-22292 - eZDemo with content broken in ezpublish-community

https://jira.ez.no/browse/EZP-22292

Fix for Fatal error: Call to a member function hasChildNodes() on a non-object in /var/www/html/ezpublish5/vendor/ezsystems/ezpublish-kernel/eZ/Publish/Core/FieldType/XmlText/Type.php on line 125 503 Service Unavailable