JS error - Uncaught Sortable: `el` must be an HTMLElement, not [object Undefined]

When we use the select2 element as a facet widget then we get the following error.

JS error - Uncaught Sortable: `el` must be an HTMLElement, not [object Undefined]

This was caused by the following code part.

var $list = $select.next('.select2-container').find('ul.select2-selection__rendered');

Where the list length is equal to 0.

I propose that we add a extra check to see if the list exists.