Conversation memory entity merge stop forcing data to become lower case.

[curtisman]

• Create a new function mergeConcreteEntitiesEx (based on current mergeConcretEntities
  • won't force data to be lower case regardless of whether merge is case-sensitive or not.
  • In the case-insensitive case, it will pick the first version it encountered.
  • The new code avoid extra conversion of concrete entity to merged entity for the RHS and directly merge to and existing merged entity compare to the old code.
  • Added unit test for this new function.
• TOOD: after more testing for stability, replace mergeConcreteEntities which currently forces all the resulting entity data to be lower case.