[Revamp Shipping Labels • Customs] Sync form

[toupper]

Part of: #13784

Description

With this PR we sync the customs form to be sent remotely. We also implement the logic of whether the customs information is completed, and keep the customs view model so the data can be edited after the view is closed and re-opened.

Steps to reproduce

1. Tap on Create Shipping Label on an order
2. Tap on the Customs pencil
3. Fill the customs form
4. Tap on Save on Customs Details
5. Check that the Customs badge is set to Completed in the Create Shipping Labels
6. Open again the Customs form. Check that you can edit the data.

Verify in Xcode through a breakpoint in onCustomsFormFilled: in WooShippingCreateLabelsViewModel to verify that the data is changed.

Testing information

We don't sync the data remotely yet, we will test that the customs information is properly sent after implementing the shipping label request.

We also fix here this comment where selections aren't being preserved on device rotation. Here, as we keep a reference to the WooShippingCustomsFormViewModel the input data remains.

Screenshots

Simulator.Screen.Recording.-.iPhone.16.-.2025-01-23.at.11.03.51.mp4

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

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• Manual Testing: The author listed all the tests they ran, including smoke tests when needed (e.g., for refactorings). The reviewer confirmed that the PR works as expected on all devices (phone/tablet) and no regressions are added.

[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	pr14959-0fafeb8
	Version	21.4
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	0fafeb8
	App Center Build	WooCommerce - Prototype Builds #12693

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

[rachelmcr]

Works as expected!

We don't sync the data remotely yet, we will test that the customs information is properly sent after implementing the shipping label request.

We did already implement support for the shipping label purchase (as part of M1). But for the full flow to make sense I believe we need to limit the customs form to only international shipments.

[rachelmcr]

I'm curious about this; won't we eventually need to include the package ID/name so we can support multiple shipments (where each shipment may have its own customs form)?

[toupper]

Good point, I updated the comment here 0fafeb8

[wpmobilebot]

Version 21.5 has now entered code-freeze, so the milestone of this PR has been updated to 21.6.