Opaque error message for bad chromosome names

[abought]

Files with malformed chromosomes sometimes generate the following error:

[failure][2021-03-08T20:52:35+00:00] An error prevented this step from completing
value too long for type character varying(5)

We should:

1. Identify common reasons for bad values and improve the validation step to prevent these from being uploaded, and
2. Improve the error message for values that make it through