Sorting a dropdown column with a filter does not work

Related to issue #2808, when using a drop-down with a filter to show the editDropdownValueLabel instead of the editDropdownIdLabel, and we have sortCellFiltered: true set, ui-grid incorrectly passes a row entity to the filter instead of the context. This prevents us from getting information about the column definition, in order to sort by filtered values.

Please see Codepen demonstrating the issue here, and a partial workaround here.