Error messages are not imported during run import
When importing a WorkfowRun that contains error messages into provenance (creating a 'husk run'), the error messages are lost. I forgot to inject these.
A related problem is that I'm not parsing the error messages from the serialized string form of a Map into a real Map (which I'll need to use). Though it's probably better to find a better way to serialize this map; the string form of the map is hard to parse since error messages can contain "=" and ",".