[Shipping Labels Revamp] Fix custom package dimension units

[ThomazFB]

Why

Every Package request comes with the Store Options data. This data is essential for the entire package selection structure, but the data wasn't being held by the main ViewModel, which blocked some scenarios where Store Options were required after the request.

How

Updates the Package selection flow to keep the StoreOptions data returned by the Packages endpoint, and map the dimensions unit in it to the Custom package creation, allowing the Custom package to keep the correct unit type.

How to Test

1. Simply make sure that all three types of Package selection are working as expected.

Update release notes:

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

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• 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 big (tablet) and small (phone) in case of UI changes, and no regressions are added.

[wpmobilebot]

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	App Name	WooCommerce-Wear Android
	Platform	⌚️ Wear OS
	Flavor	Jalapeno
	Build Type	Debug
	Commit	a7633b5
	Direct Download	woocommerce-wear-prototype-build-pr13214-a7633b5.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	a7633b5
	Direct Download	woocommerce-prototype-build-pr13214-a7633b5.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 70.73171% with 12 lines in your changes missing coverage. Please review.

Project coverage is 40.62%. Comparing base (9153b1d) to head (a7633b5).
Report is 8 commits behind head on trunk.

Files with missing lines	Patch %	Lines
...ckages/datasource/WooShippingLabelPackageMapper.kt	0.00%	8 Missing ⚠️
...ckages/WooShippingLabelPackageCreationViewModel.kt	71.42%	1 Missing and 1 partial ⚠️
...i/orders/wooshippinglabels/packages/ui/UIModels.kt	84.61%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk   #13214      +/-   ##
============================================
+ Coverage     40.61%   40.62%   +0.01%     
- Complexity     6386     6388       +2     
============================================
  Files          1351     1351              
  Lines         77525    77562      +37     
  Branches      10659    10665       +6     
============================================
+ Hits          31486    31512      +26     
- Misses        43259    43270      +11     
  Partials       2780     2780              

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[atorresveiga]

@ThomazFB, do you think we need other store options class for packages?
We already refresh store options when we start the purchase flow with the ObserveStoreOptions, and we cache that data. I might be missing something, but re-using the use case could help us maintain a single source of truth. WDYT?

[ThomazFB]

Hey @atorresveiga! I considered using it, but the thing is: these store options we're talking about are coming from the Package request we have to do to display the selection data; it comes for free. while re-using the use case would add complexity or maybe an additional request to a data that's already there for us to use. WDYT?

[ThomazFB]

Here's an example of what I'm talking about:

[atorresveiga]

LGTM!