Update customs schema

[selanthiraiyan]

There seems to be a mismatch in the customs schema.

We need to investigate what is missing and update how we handle customs response while purchasing shipping labels.

Internal - p1742332109868749-slack-C05VBLKHHV1

Android discussion about this issue - woocommerce/woocommerce-android#13759 (comment)

[dangermattic]

🚫 Please add a type label (e.g. type: enhancement) and a feature label (e.g. feature: stats) to this issue.

[selanthiraiyan]

We discovered that we need to send customs information when getting shipping rates. We should check if iOS is sending this information.

Internal - p1742838304431159/1742332109.868749-slack-C05VBLKHHV1.

[selanthiraiyan]

Based on this input from @ThomazFB p1743066521402129/1742978311.923109-slack-C03L1NF1EA3 check the following items while sending customs info.

The origin_country is not the country code, but the country name + code.
The box_id on Android always uses the default_package value, I see that iOS is sending a Box2Cube value. This id came from a carrier-defined package?
I'm also noticing that the id field is using a fixed shipment_0 value, was that something provided by the package data or it's set by the iOS app? On Android, we have a large generated id by the API response. E.g. 2537d64eb2dd497092cf0c6564f3bfce.