[Feature] Extend CellState.filteredCellValue() to allow implement custom PlutoColumnType with proper set new value checks.

[slavap]

Currently there is the following code in CellState.filteredCellValue()

if (column.type.isSelect) {
      return column.type.select.items.contains(newValue) == true
          ? newValue
          : oldValue;
    }

When I'm implementing some custom PlutoColumnType, I would like to have an ability to check newValue by myself.
Please add the following method to PlutoColumnType:

(bool, dynamic) filteredValue({
    dynamic newValue,
    dynamic oldValue,
  }) => (false, newValue);

so I can override it in my custom PlutoColumnType.
And call it from the CellState.filteredCellValue() as the first statement:

final typeResult = column.type.filteredValue(oldValue: oldValue, newValue: newValue);
if (typeResult.$1) return typeResult.$2; 

//... rest of current CellState.filteredCellValue() code