Comet: Bulkrax ingest with filesets error

We should eliminate this error that we found to be generated on filesets ingests.

messageError performing FileSetAttachedEventJob (Job ID: af296cc5-63f8-43a4-8bde-4ff75ec74087) from Sidekiq(default) in 3.55ms: NoMethodError (undefined method `title' for nil:NilClass):