JBDS shouldn't report empty error code

JBDS tooling reports an error, when there is error event with no error code configured:

Error Error 1(java.lang.RuntimeException) has no Error Code

This should not be reported, because empty error code means we are listening to all errors, which is valid use case.

Sample definition attached.

plugin version:
BPMN2 Modeler - Diagram Editor 1.4.3.Final-v20180418-1358-B1