Allow blank 'author' when running local prods
LbMCSubmit creates yaml files with author: null
for all requests, since this is overwritten elsewhere.
For local tests we don't want MC liaisons to have to modify these large YAML files to change this field.
BEGINRELEASENOTES
- ProductionManagementSystem CHANGE: allow empty author field in dirac-production-request-run-local
ENDRELEASENOTES