reset method
Implementation
void reset(String name) {
final config = _configs[name] as JarFieldConfig;
final state = _fields[name] as JarFieldState;
_updateField(
name,
state.copyWith(
value: config.defaultValue,
error: null,
isDirty: false,
isTouched: false,
isValidating: false,
isDisabled: config.disabled,
),
);
}