Do not terminate when a grid calculation reads a cell index out of range

RigAllGridCellsResultAccessor bounds checked the cell index with an assert that is compiled out in release builds, and then called std::vector::at(), which throws. RimGridCalculation::getActiveCellValues() calls the accessor from an OpenMP loop, using active cell indices from the destination case to read results from the source case, so an index beyond the source result vector threw an exception that could not escape the parallel region and called std::terminate. Return undefined for an out of range index instead, and guard against a null result accessor.

ApplicationLibCode/ProjectDataModel/RimGridCalculation.cpp

@@ -635,6 +635,7 @@ std::vector<double> RimGridCalculation::getActiveCellValues( const QString&
     size_t gridIndex = 0;
     auto   resultAccessor =
         RigResultAccessorFactory::createFromResultAddress( eclipseCaseData, gridIndex, porosityModel, timeStepToUse, resAddr );
+    if ( resultAccessor.isNull() ) return {};
 
 #pragma omp parallel for
     for ( int i = 0; i < static_cast<int>( activeReservoirCells.size() ); i++ )