Migrates ./Lts/Viewer successfully to Qt6

qt6-after/qt6-migrated-legatus/Lts/Viewer/LtsDataView/data_delegate.cpp

@@ -24,7 +24,7 @@ DataDelegate::DataDelegate(QObject *parent)
 
 QString DataDelegate::displayText(const QVariant &value, const QLocale &locale) const
 {
-  if (value.type() == QVariant::Type::DateTime)
+  if (value.userType() == QMetaType::QDateTime)
     return DTG::toString(value.toDateTime());
   return QStyledItemDelegate::displayText(value, locale);
 }