Verifies that a workflow declaring a policy has an authorizer to enforce it.
AshWorkflow.Transformers.AddPolicies generates nothing when
Ash.Policy.Authorizer is absent, so a policy on a step or on the undo
block was accepted and then never enforced. Every caller was authorized,
including the ones the policy named. Declaring an authorization rule and
getting none is the one failure that should never be silent, so it is a
compile error.