Potentially remove internal filter_message_top_n

[maximusunc]

Maybe this is a bug somewhere in Aragorn, but sometimes the workflow is included in the call to aragorn_ranker. In that workflow is the filter_message_top_n operation, which isn't a valid operation and scorer throws a 422. I'm not sure why the workflow is included. We either need to remove this pseudo operation or find out why the workflow is being included in subservice queries.

[maximusunc]

Never mind. I saw an error from scorer and then tried to pass the response through scorer myself, but the return message from Aragorn does include the workflow to show the user what workflow was run. Though that now makes me worried that some upstream service might do some TRAPI validation (they really should) and they would end up barfing on our response. So I'm going to double down on removing it as an internal pseudo workflow operation. We either need to remove it or get filter_message_top_n into the TRAPI spec.