DMN runtime not using the kiecontainer root classloader to load classes

The FunctionDefNode is not using the kie container root classloader to load classes. I even added a comment for that, just a shame comments are not executable:

https://github.com/kiegroup/drools/blob/master/kie-dmn/kie-dmn-feel/src/main/java/org/kie/dmn/feel/lang/ast/FunctionDefNode.java#L98-L99

                        // might need to explicitly use a classloader here
                        Class<?> clazz = Class.forName( clazzName );

To reproduce the problem, create a java class with a static method, add it to the kjar, create a DMN model that invokes that model, and try to execute.