fix Warning

qt6-after/qt6-migrated-legatus/Lts/Viewer/SituationMap/Symbology/symbol_result.cpp

@@ -196,7 +196,7 @@ void SymbolResultWatcherComboxBox::onResultReady()
     return;  // should NEVER happen! (Which object should have triggered the signal???)
 
   int idx = m_comboBox->findData(QVariant::fromValue(this), m_role);
-  const QImage &img = symResult->symbolImage().image();
+  const QImage img = symResult->symbolImage().image();
 
   m_comboBox->setItemIcon(idx, QPixmap::fromImage(img));