allowClear bug with multiple select from upstream select2 library

[blms]

This bug from upstream Select2 is present in DAL: select2/select2#3335

The following monkey-patch was posted in that thread:

var AllowClear = $.fn.select2.amd.require('select2/selection/allowClear');
var _handleKeyboardClearOriginal = AllowClear.prototype._handleKeyboardClear;

AllowClear.prototype._handleKeyboardClear = function(_, evt, container) {
  if (this.$element.prop('multiple')) {
    return;
  }

  _handleKeyboardClearOriginal.call(this, _, evt, container);
};

I believe this could be applied when select2 is initialized in DAL, as it seems the select2 maintainers haven't been proactive in fixing this bug in the past 10 years.