Allow required report types without a report template (e.g. for training reports)

Users want to add a required report type (e.g. a training report) to a service without being forced to assign a report template. Today the system requires a template for each required report type in service settings, which blocks adding training or other internal-only reports that don't need a template or get their template added manually later.

Why it matters: Inspectors and schedulers need training report buckets and similar report types on jobs; making the template optional in service settings would let them set this up without a workaround.