Adapts shared tests and common code to generated rtiddsgen API

Updates test suites and Lts/Common consumers to plain member access.

qt6-after/qt6-migrated-legatus/Lts/Common/CodeGen/svc_json.cpp.grantlee

@@ -48,6 +48,18 @@ QJsonValue toJson(qint64 vec)
 {
   return QJsonValue(QString::number(vec));
 }
+// IDL 64-bit integers map to int64_t, which is 'long' on LP64 and therefore
+// distinct from qint64 ('long long'); without this overload the generic
+// toJson(std::vector<T>) is ambiguous for sequence<int64_t> members.
+QJsonValue toJson(long vec)
+{
+  return QJsonValue(QString::number(vec));
+}
+template<>
+long fromJson(const QJsonValue &val, type<long>)
+{
+  return val.toString().toLong();
+}
 
 // std::string
 QJsonValue toJson(const std::string &element)