Autocomplete light - "select2" has already been registered." JS warning

[davmlaw]

We sometimes get "autocomplete_light.js:17 The DAL function "select2" has already been registered." in Javascript console

[davmlaw]

Shariant testing required: Make sure autocompletes are still functional

Raised issue on library to try and make global fix: yourlabs/django-autocomplete-light#1406