async isSelectedItem(itemPosition) {
        const items = await $(this.rootElement).$$('option');
        if (items[itemPosition]) {
            return items[itemPosition].isSelected();
        }
        return false;
    }
Returns true when the select item with item position is selected.
@method
@returns {bool}
@param {number} itemPosition - The base 0 index of the select item.