Make noUISlider module/lib a soft dependency

So I’m inclined to keep this as is. If someone forgets to get the library then I’ll get more tickets about the slider not working. Don’t see the harm in downloading the library

Leaning toward won’t fix

It was just an idea, since I saw there was a lot of effort to remove all the jquery_ui dependencies recently.
Some modules also add a requirement message in the status page in case the library is missing.
And composer can handle library updates when using the npm-asset method (or composer-merge plugin).
Here is an example from js-cookie ✨ Support local library file Active

But feel free to close it if no-one else objects.

Definitely appreciate the suggestion. ✨ Demonstrate a better noui slider library integration. Active we are going to clean up slightly so it just uses the mirror copy. So CDN should be removed so hopefully that addresses any concern.