Fix charts not recognising en-AU as a locale

[engram-design]

Just uncovered an interesting issue, when our site's locale is set to en-AU (as it most often is for us), the Commerce charts seem to render ₹ instead of a dollar sign.

Diving into the code it relies on:

https://github.com/craftcms/cms/blob/develop/src/web/assets/d3/D3Asset.php#L57-L75

It'll try and locate a lib/d3-format/en-AU.json file, but since that doesn't exist, it'll find the first en-*.json file, which happens to be en-IN.json. I can see there's the default for en-US, but it never reaches that if there's at least one other english-variant file.

Adding this file (duplicating en-US) works as expected.

[brandonkelly]

Thanks for pointing that out! This is a problem for more than just en-AU, so I took a different approach for the fix, but the result will be the same for you.

[engram-design]

Even better, thanks!