Shipping Label: Rename views and properties for shipment items

[itsmeichigo]

Part of #15307

Description

This PR handles the renaming of shipment item rows and properties to avoid ambiguity when moving them to different shipments.

Steps to reproduce

There are only renaming, so please feel free to test #15418 again to ensure everything works correctly.

Testing information

Tested the shipment row on simulator iPhone 16 Pro iOS 18.2 and confirmed that the WIP still works correctly.

Screenshots

N/A

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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.

Reviewer (or Author, in the case of optional code reviews):

Please make sure these conditions are met before approving the PR, or request changes if the PR needs improvement:

• The PR is small and has a clear, single focus, or a valid explanation is provided in the description. If needed, please request to split it into smaller PRs.
• Ensure Adequate Unit Test Coverage: The changes are reasonably covered by unit tests or an explanation is provided in the PR description.
• 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.

[dangermattic]

	1 Warning
⚠️	View files have been modified, but no screenshot or video is included in the pull request. Consider adding some for clarity.

Generated by 🚫 Danger

[selanthiraiyan]

Thanks for taking care of this. The renaming makes perfect sense. 🚀

[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	pr15422-3c9155c
	Version	22.0
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	3c9155c
	App Center Build	WooCommerce - Prototype Builds #13414

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