feat: use hardcoded error message when error class has a nil message
feat: use hardcoded error message when error class has a nil message

pact-foundation/pact_broker,tancnle/pact_broker,tancnle/pact_broker,tancnle/pact_broker,pact-foundation/pact_broker,pact-foundation/pact_broker,tancnle/pact_broker,pact-foundation/pact_broker