refactor(dmq): adapt publisher server with new 'DmqMsg' structure

Following the move of operational certificate and cold verification out of the signed payload.

Author: jpraynaud

internal/mithril-dmq/src/publisher/server/pallas.rs

@@ -264,13 +264,12 @@ mod tests {
             msg_payload: DmqMsgPayload {
                 msg_id: vec![0, 1],
                 msg_body: vec![0, 1, 2],
-
                 kes_period: 10,
-                operational_certificate: vec![0, 1, 2, 3, 4],
-                cold_verification_key: vec![0, 1, 2, 3, 4, 5],
                 expires_at: 100,
             },
             kes_signature: vec![0, 1, 2, 3],
+            operational_certificate: vec![0, 1, 2, 3, 4],
+            cold_verification_key: vec![0, 1, 2, 3, 4, 5],
         }
     }