Empty results aren't overwriting the default None

[maximusunc]

Here: https://github.com/NCATSTranslator/workflow-runner/blob/main/app/server.py#L184 a base message is created, which has results as None for default. Then below that we update it with the incoming message. If that message has an empty results list, reasoner-pydantic doesn't do anything and leaves it as None. This could either be fixed on reasoner-pydantic side, or we initialize that first base message with better defaults in this code.