Merge branch 'XX-4018/AltUdContactBug' into 'XX-4019/NewOrLoadAltUd'

Fix contact marshal mismatch bug

See merge request !324

bindings/ud.go

@@ -256,7 +256,7 @@ func (ud *UserDiscovery) GetContact() ([]byte, error) {
 		return nil, err
 	}
 
-	return json.Marshal(c)
+	return c.Marshal(), nil
 }
 
 // ConfirmFact confirms a fact first registered via AddFact. The confirmation ID