[FormBuilderCheckbox]: Support error styling

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Package/Plugin version

10.2.0

### What you'd like to happen

I'd like my checkbox to be red when the field has an error.

I have declared:

```dart
FormBuilderCheckbox(
name: 'consent',
side: WidgetStateBorderSide.resolveWith((states) {
if (states.contains(WidgetState.error)) {
return BorderSide(color: Colors.red);
}

return null;
}),
title: Text('I have read the Terms & Conditions.'),
validator: (value) => value != true ? 'Please check above checkbox to proceed' : null,
),
```

Unfortunately it doesn't work because the Checkbox is never told to be "in error". So, in my snippet above, `states` never contains `WidgetState.error`. It can be solved with a one-liner, we just have to forward the property `hasError` to the CheckboxListTile constructor:

See https://github.com/flutter-form-builder-ecosystem/flutter_form_builder/compare/main...ncuillery:flutter_form_builder:patch-1

Without the change|With the change
----------|------------
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Would have accept a PR with this change?

### Alternatives you've considered

_No response_

### Aditional information

The problem would also be fixed when using the Material theme instead of the explicit `side` property. Like this:

```dart
Theme(
data: ThemeData(
checkboxTheme: CheckboxThemeData(
side: WidgetStateBorderSide.resolveWith(
(states) {
if (states.contains(WidgetState.error)) {
return BorderSide(color: Colors.red);
}

return null;
},
),
),
),
child: FormBuilderCheckbox(
name: 'consent',
title: Text('I have read the Terms & Conditions.'),
validator: (value) => value != true ? 'Please check above checkbox to proceed' : null,
),
),
```