Please allow us to disable the icons of the chips

[shawnAshton]

MultiSelectChipDisplay could have a bool Parameter called showCheckmark this could be used in multi_select_chip_display.dart. theWidget _buildItem(MultiSelectItem<V> item, BuildContext context) {...} function uses the ChoiceChip widget. If you add the following line showCheckmark: showCheckmark, this would allow users of your widgets to prevent the showing of the check mark icons that appear within the chips.