Update OrdersRemote with async/throws network methods to parse orders response in a background thread

[jaclync]

For WOOMOB-981

Just one review is required.

Description

Updates OrdersRemote.loadAllOrders and OrdersRemote.searchOrders methods to use modern async/await interface instead of completion handlers. This change improves response handling by ensuring it doesn't occur on the main thread and follows current Swift concurrency best practices. These two methods are the only ones in OrdersRemote that fetch and parse a list of orders, which include meta_data field that can include any number of values resulting in a large response size.

The updated methods now:

• Use async throws instead of completion handlers which parse the response on the main thread
• Integrate with existing async/await patterns in the codebase

All call sites have been updated to maintain compatibility:

• OrderStore methods use Task blocks with @MainActor for thread safety
• Tests have been converted to async/await syntax
• UI components maintain their existing interfaces

Steps to reproduce

• Feel free to put a breakpoint in Order.swift init(from:)
• Go to the Orders tab --> the breakpoint in Order.swift should not be on the main thread
• Disable the breakpoint
• Pull to refresh --> the UI should be smooth while orders are being loaded in the background
• Search for orders --> the UI should be smooth while orders are being loaded in the background

Testing information

I tested on iPad A16 iOS 18.4 simulator.

---

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

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

	App Name	WooCommerce iOS Prototype
	Build Number	pr15982-8377aba
	Version	22.9
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	8377aba
	Installation URL	7n513n1naqp7g

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 23.0. This milestone is due in less than 2 days. Please make sure to get it merged by then or assign it to a milestone with a later deadline.

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[iamgabrielma]

Works great! Thanks for your work modernizing those.

I left a couple of nits, feel free to address them or not 👍

[iamgabrielma]

nit: The alignment of these props seems to be off!

[jaclync]

Fixed the alignment in 8377aba.

[iamgabrielma]

nit: Since we're updating the test signature we can update the test name to use snake case as well 🐍 , ideally with when/then too.

[jaclync]

Makes sense, updated in aa00e4c.