DMN DTAnalysis negation of non-compliant DMN missing enum

When a DT is missing an Enum for the column entry, usually a message was reported.
In general, DMN compliant model would enumerate input entries.

However, non-compliant DMN model might omit enumeration.
Under specific circumstances (negation) the message was not reported and further calculation of the negation over the domain was not correctly performed.

This jira fixes this problem for non-compliant DMN model (despite being non-compliant).