Update modules/vaos/app/services/vaos/v2/unified/slots_service.rb

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: JunTaoLuo

modules/vaos/app/services/vaos/v2/unified/slots_service.rb

@@ -38,7 +38,7 @@ def slots_for(provider:, start_dt:, end_dt:, clinical_service: nil, appointment_
         attr_reader :user
 
         def fetch_va_slots(provider, start_dt, end_dt, clinical_service)
-          raise Common::Exceptions::ParameterMissing, 'service_type' if clinical_service.blank?
+          raise Common::Exceptions::ParameterMissing, 'clinical_service' if clinical_service.blank?
 
           if provider.location_id.blank? || provider.id.blank?
             raise Common::Exceptions::UnprocessableEntity.new(