Fix LtsUtilsCore include path and BUILD_RTI guards

- LtsUtilsCore/CMakeLists.txt: Fixed include path from /.. to /../..
  for both LtsUtilsCoreHeaderOnly and LtsUtilsCore targets
- session_handler.h: Added #if BUILD_RTI guard around dds_connector.h include
- data_writer_task.h: Removed override specifier from stub methods
  when BUILD_RTI=OFF (base class interface not available)

BUILD_RTI=OFF: 0 errors (validated)
BUILD_RTI=ON: Progresses further, external dependency errors remain
  (svcIsmCommon not available in Docker image - not migration issue)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-legatus/Lts/Services/RoutingServiceNG/data_writer_task.h

@@ -37,7 +37,7 @@ public:
   void writeSamples();
 #else
   // Stub methods when BUILD_RTI is disabled
-  void enqueue(SampleWriterInterface* /*swi*/) override {}
+  void enqueue(SampleWriterInterface* /*swi*/) {}
   void shutdown() {}
   bool waitForData() { return false; }
   SampleWriterInterface* getNextSampleWriter() { return nullptr; }

qt6-after/qt6-migrated-legatus/Lts/Services/RoutingServiceNG/session_handler.h

@@ -14,7 +14,10 @@
 #include "rsccommon_export.h"
 #include "logger.h"
 #include "session.h"
+
+#if BUILD_RTI
 #include <DDS/DDSConnector/dds_connector.h>
+#endif
 
 namespace LtsPluginManager
 {