style: fix lint warnings

Author: deandreamatias

lib/src/fields/form_builder_date_time_picker.dart

@@ -284,7 +284,6 @@ class _FormBuilderDateTimePickerState extends FormBuilderFieldDecorationState<
       case InputType.date:
         return DateFormat.yMd(languageCode);
       case InputType.both:
-      default:
         return DateFormat.yMd(languageCode).add_Hms();
     }
   }
@@ -309,8 +308,6 @@ class _FormBuilderDateTimePickerState extends FormBuilderFieldDecorationState<
           newValue = combine(date, time);
         }
         break;
-      default:
-        throw 'Unexpected input type ${widget.inputType}';
     }
     if (!mounted) return null;
     final finalValue = newValue ?? currentValue;

lib/src/widgets/grouped_radio.dart

@@ -237,7 +237,6 @@ class _GroupedRadioState<T> extends State<GroupedRadio<T?>> {
           child: Row(children: widgetList),
         );
       case OptionsOrientation.wrap:
-      default:
         return SingleChildScrollView(
           child: Wrap(
             spacing: widget.wrapSpacing,