Wcf fix

Suggestion to fix Bug #14473 - WCF SerializationException. 

In case using interface and Inheritance in service method was thrown System.Runtime.Serialization.SerializationException: Type
'Dante.Contracts.Authentication.PinAuthenticationCommand' is unexpected. The
type should either be registered as a known type, or DataContractResolver
should be used. Known types was registred, but not used in Serialization.