[Shipping Labels Revamp] Introduce carrier package selection UI

[ThomazFB]

Summary

Fix issue #12745 by introducing the Carrier compose UI alongside the basic selection logic for it. It also introduced the scaffold to supply actual data to the view when the endpoints are available.

Screen Capture

https://github.com/user-attachments/assets/eb3e97ab-2ebf-4418-a052-65b8dd812b83

How to Test

1. This is a purely UI implementation, so the code is not operational or testable as it is. It's hidden under a feature flag to avoid being reachable to our users.

Update release notes:

• [x] 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:

• [x] 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.
• [x] Ensure Adequate Unit Test Coverage: The changes are reasonably covered by unit tests or an explanation is provided in the PR description.
• [x] 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 big (tablet) and small (phone) in case of UI changes, and no regressions are added.

[dangermattic]

	1 Warning
:warning:	This PR is larger than 300 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.

Generated by :no_entry_sign: Danger

[wpmobilebot]

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

	App Name	WooCommerce-Wear Android
	Platform	⌚️ Wear OS
	Flavor	Jalapeno
	Build Type	Debug
	Commit	6de6c91936ae9e12ac1876ba030cf3d4488bcd6c
	Direct Download	woocommerce-wear-prototype-build-pr12902-6de6c91.apk

[wpmobilebot]

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

	App Name	WooCommerce Android
	Platform	📱 Mobile
	Flavor	Jalapeno
	Build Type	Debug
	Commit	6de6c91936ae9e12ac1876ba030cf3d4488bcd6c
	Direct Download	woocommerce-prototype-build-pr12902-6de6c91.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 35.79545% with 113 lines in your changes missing coverage. Please review.

Project coverage is 40.18%. Comparing base (7e3c448) to head (6de6c91). Report is 35 commits behind head on trunk.

Files with missing lines	Patch %	Lines
...ckages/datasource/FetchCarrierPackagesFromStore.kt	0.00%	69 Missing :warning:
.../packages/components/WooShippingPackageListItem.kt	0.00%	28 Missing :warning:
...ckages/WooShippingLabelPackageCreationViewModel.kt	72.72%	8 Missing and 1 partial :warning:
...oid/ui/orders/wooshippinglabels/packages/Models.kt	84.78%	7 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## trunk #12902 +/- ## ============================================ - Coverage 40.21% 40.18% -0.04% - Complexity 5793 5798 +5 ============================================ Files 1255 1258 +3 Lines 71397 71539 +142 Branches 9968 9979 +11 ============================================ + Hits 28713 28745 +32 - Misses 40046 40155 +109 - Partials 2638 2639 +1 ```

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