Add assert for code scan alert 550

src/gui/src/ScreenSetupModel.cpp

@@ -30,6 +30,11 @@ ScreenSetupModel::ScreenSetupModel(
       m_Screens(screens),
       m_NumColumns(numColumns),
       m_NumRows(numRows) {
+
+  // bound rows and columns to prevent multiply overflow.
+  // this is unlikely to happen, as the grid size is only 3x9.
+  assert(m_NumColumns < 100 && m_NumRows < 100);
+
   if (m_NumColumns * m_NumRows > screens.size())
     qFatal(
         "Not enough elements (%lld) in screens QList for %d columns and %d "