[Shipping Labels Revamp] Add Package template loading and recovery feedback

[ThomazFB]

Why

As it is, the current Package Selection flow handles a Custom package being saved as a template as an optimistic operation, but after some team discussions, we decided to keep direct feedback to the user to allow them to know if it failed or not.

How

This PR introduces not only loading feedback for the Custom package creation but also an Error dialog that suggests the user use the package without saving it as a template if the problem persists as a quick solution for any custom package creation unavailability on the store.

Screen Capture

Error Handling

Screen_recording_20250102_194433.mp4

Loading feedback

Screen_recording_20250102_200127.mp4

How to Test

Scenario 1 - Loading feedback

1. Go to the Package selection flow during the new Shipping Labels creation flow
2. Define a Custom package and mark the save as template checkbox
3. Complete the form and add the package
4. Ensure the loading feedback is displayed and dismissed as expected

Scenario 2 - No Loading feedback

1. Go to the Package selection flow during the new Shipping Labels creation flow
2. Define a Custom package and DO NOT mark the save as template checkbox
3. Complete the form and add the package
4. Ensure no loading feedback was displayed, as the package didn't require any network request

Scenario 3 - Error handling

⚠️ In order to force an error scenario, I recommend hardcoding the WooShippingLabelPackageRepository.createCustomPackage function to the following:

    suspend fun createCustomPackage(
        site: SiteModel = selectedSite.get(),
        requestData: List<CustomPackageCreationRequestData>
    ): WooResult<List<PackageDAO>> {
        site.apply {  }
        requestData.apply {  }
        return WooResult(WooError(WooErrorType.GENERIC_ERROR, BaseRequest.GenericErrorType.UNKNOWN))
    }

1. Go to the Package selection flow during the new Shipping Labels creation flow
2. Define a Custom package and mark the save as template checkbox
3. Complete the form and add the package
4. Ensure the error dialog is displayed
5. Hit the Proceed button and verify that the Package is selected to the Shipping Labels form

Update release notes:

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

[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	99625db
	Direct Download	woocommerce-wear-prototype-build-pr13236-99625db.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	99625db
	Direct Download	woocommerce-prototype-build-pr13236-99625db.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 68.00000% with 16 lines in your changes missing coverage. Please review.

Project coverage is 40.63%. Comparing base (bcbbde1) to head (5029816).

Files with missing lines	Patch %	Lines
...ckages/WooShippingLabelPackageCreationViewModel.kt	46.66%	13 Missing and 3 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk   #13236      +/-   ##
============================================
- Coverage     40.64%   40.63%   -0.02%     
+ Complexity     6387     6385       -2     
============================================
  Files          1351     1351              
  Lines         77444    77449       +5     
  Branches      10650    10655       +5     
============================================
- Hits          31479    31469      -10     
- Misses        43186    43200      +14     
- Partials       2779     2780       +1     

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[atorresveiga]

Thanks for working on this, Thomaz. Nice touch enabling continued flow when the package saving fails.

LGTM!