fix: Ensure stack is not empty before calling top.

source/RobotAPI/libraries/armem/component/RemoteGuiAronDataVisitor.h

@@ -96,7 +96,10 @@ namespace armarx::armem
         template <class Navigator>
         void addValueLabel(Navigator& n, const std::string& typeName)
         {
-            groups.top().addChild(Label(this->makeValueLabelText(n, typeName)));
+            if (not groups.empty())
+            {
+                groups.top().addChild(Label(this->makeValueLabelText(n, typeName)));
+            }
         }
         template <class Navigator>
         std::string makeValueLabelText(Navigator& n, const std::string& typeName)