Load relationship on widget

class AddProductCardWidget extends Widget implements HasForms
{
    use InteractsWithForms;
    use InteractsWithPageTable;

    protected static string $view = 'filament.resources.product-resource.widgets.add-product-card-widget';

    protected function getTablePage(): string
    {
        return ManageProductCards::class;
    }

    public function form(Form $form): Form
    {
        return $form->schema([
            Select::make('rate_type_id')
                ->required()
                ->live()
                ->relationship('productCard', 'name'),
        ]);
    }
}

    protected function getHeaderWidgets(): array
    {
        return [
            SpecialityResource\Widgets\AddProductCardWidget::class,
        ];
    }