Skip (de)serialization of single signature authentication_status

For retrocompatibility with previously stored signatures (with open
messages in aggregator).

Author: Alenar

mithril-common/src/entities/single_signatures.rs

@@ -29,6 +29,7 @@ pub struct SingleSignatures {
     pub signed_message: Option<String>,
 
     /// Status of the authentication of the signer that emitted the signature
+    #[serde(skip)]
     pub authentication_status: SingleSignatureAuthenticationStatus,
 }