docs: public String getRelyingPartyIdentifier(final Service service, final WsFederationConfiguration configuration) {
          val relyingPartyIdentifier = configuration.getRelyingPartyIdentifier();
          if (service != null) {
              val registeredService = this.servicesManager.findServiceBy(service);
              RegisteredServiceAccessStrategyUtils.ensureServiceAccessIsAllowed(service, registeredService);
              if (RegisteredServiceProperty.RegisteredServiceProperties.WSFED_RELYING_PARTY_ID.isAssignedTo(registeredService)) {
                  LOGGER.debug("Determined relying party identifier from service [{}] to be [{}]", service, relyingPartyIdentifier);
                  return RegisteredServiceProperty.RegisteredServiceProperties.WSFED_RELYING_PARTY_ID.getPropertyValue(registeredService).getValue();
              }
          }
          LOGGER.debug("Determined relying party identifier to be [{}]", relyingPartyIdentifier);
          return relyingPartyIdentifier;
      }