WFCORE-204 CLU GUI upload for op params with ModelType.BYTES

This will throw an IAE if the server-side author screwed up and there is no "type" declaration. That shouldn't happen with folks using "modern" subsystem authoring, but it's possible with some old stuff someone outside WildfFly may have.

You can do an isDefined check, or, since the ModelType of "type" is by spec supposed to be ModelType, you can do this:

ModelNode typeDesc = prop.getValue().get("type");
if (typeDesc.getType() == ModelType.TYPE && typeDesc.asType() == ModelType.BYTES) {

That will avoid failing on any bogus strings (e.g. "long") people may have stuck into a "type" description. Again, anything in WildFly/EAP itself shouldn't have such bogus stuff, so this is just being careful about external stuff.