fix: copy c'tor of GoalReachedMonitor not working atm

source/armarx/navigation/server/Navigator.cpp

@@ -468,6 +468,7 @@ namespace armarx::navigation::server
 
         ARMARX_TRACE;
 
+        goalReachedMonitor = std::nullopt;
         goalReachedMonitor =
             GoalReachedMonitor(graphBuilder.goalPose(), *config.scene, GoalReachedMonitorConfig());