Bug when color variant does not have the same sizes available

[gregjotau]

A bit related to #1407

Discussed this with @cfxd

Observed on famme.no for the product: https://famme.no/products/seamless-tights-vortex-2

I think this is actually either a bug with Dawn or a feature. The problem that I see is that the first selected variant incudes a size which isn't sold in other colors at all. So, if the first thing you do is change the color to "Blå" and keep the size on "XXS" then there is no variant that exists there, so the fetch() function can't actually figure out a URL to fetch and find which other sizes are available.

I see two possible workarounds:

1—Add the "XXS" size to all the colors and simply set the inventory to 0; or

2—I can modify the script so that any time someone changes the options, it will automatically find and select a variant that's available in that style. See here for an example: https://www.footmotion.com.au/collections/men/products/inspire-17-male-adult?variant=38109118464186. On that variant page, the size 8 is selected, but if you click the color thumbnail to the left, you will see it switches the selected size to 8.5. You can still go back and select size 8, but whenever a selector changes it always looks for a first available variant. I haven't tried doing that with Dawn though.