[Backend Receipts] Network layer for receipt endpoint

[iamgabrielma]

Closes: #11825

Description

This PR adds the necessary network layer for the new wc/v3/orders/<order-id>/receipt endpoint, part of the Backend Receipts project ( pfoUAQ-b9-p2 ).

The endpoint has not yet landed in WooCommerce core, but it's being worked on a development branch: woocommerce/woocommerce#43502 using WooCommerce Version 8.6.0-dev-7625495467-gf50cc6b

From the app, we intend to submit a POST request to the endpoint, such as:

curl -X POST "https://mywootestingstore.mystagingwebsite.com/wp-json/wc/v3/orders/<order-id>/receipt?<consumer-key>&consumer_secret=<consumer-secret>"

And expect a response that contains a receipt_url with an URL to the order receipt, as well as an expiration_date.

{
    "receipt_url":"https:\/\/mywootestingstore.com\/wc\/file\/transient\/7e811be40195b17f82604592ed26b694868807",
    "expiration_date":"2024-01-27"
}

Testing instructions

Still not being used. Unit tests should pass.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS
	Build Number	pr11837-6017163
	Version	17.1
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	6017163
	App Center Build	WooCommerce - Prototype Builds #7820

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[iamgabrielma]

For the time being we intend to always force receipt regeneration when calling the endpoint, this might change later (specially if we end calling it upon view load or refresh control), but for the moment we'll pass true as default parameter.

[iamgabrielma]

I'm 50/50 about renaming this parameter from receiptURL to receiptURLString or similar. I went ahead with receiptURL for consistency with the API, but I can see the case for being consistent with the data type on the client instead.

[bozidarsevo]

I suppose the client will need to create URL object from it? If we always need to create URL on the client maybe we can do it when initializing Receipt. Or we have receiptURLString and have a computed property var receiptURL: URL??

[iamgabrielma]

Yes, at some point we'll create the URL object from it, but from my exploration we might not need it until the last moment in the presentation layer when we're actually invoking the WKWebView initializer with an URL(string: <url-goes-here>) .

Since we also won't do any validation regarding the contents of the URL through the business layer, the rest of the app shouldn't care if this is a valid URL or not, the web view will either return a receipt or a 404/other messages when needed, so I think I'm happy to keep it as a simple String while the data flows through the app, but the model can also map this to a different type as needed later on.

[iamgabrielma]

Only one reviewer is needed 🙇