Prior to this PR, `product_configurator_popup.js` did not support attribute selection of type `multi`. In addition, the `pos_preparation_display` did not display any attributes. Now it's possible to select attributes of type `multi` in the Point of Sale, and the preparation display shows all available attributes. closes odoo/odoo#136441 Taskid: 3497560 Related: odoo/enterprise#47834 Signed-off-by: Adrien Guilliams (adgu) <adgu@odoo.com>