[Wear App] Update wear stats loading strategy

[ThomazFB]

Summary

This is an adjustment to the Wear app targeting a more resilient approach to the Stats screen, where missing data will still allow the other stats to be displayed. This corner case can only be observed in test stores with no real activity, but it's blocking our release strategy.

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]

	2 Warnings
:warning:	Class StoreStatsDataDeserializer is missing tests, but unit-tests-exemption label was set to ignore this.
:warning:	This PR is assigned to the milestone 21.1. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

Generated by :no_entry_sign: Danger

[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	8746e2403f44c0be28174c3eceb81130c852d65e
	Direct Download	woocommerce-prototype-build-pr12946-8746e24.apk

[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	8746e2403f44c0be28174c3eceb81130c852d65e
	Direct Download	woocommerce-wear-prototype-build-pr12946-8746e24.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 62.85714% with 13 lines in your changes missing coverage. Please review.

Project coverage is 40.23%. Comparing base (e928730) to head (8746e24). Report is 193 commits behind head on trunk.

Files with missing lines	Patch %	Lines
...ndroid/wear/ui/stats/datasource/StatsRepository.kt	0.00%	12 Missing :warning:
...rce/android/wear/ui/stats/datasource/FetchStats.kt	83.33%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## trunk #12946 +/- ## ============================================ + Coverage 40.21% 40.23% +0.01% - Complexity 5793 5807 +14 ============================================ Files 1255 1255 Lines 71397 71420 +23 Branches 9968 9974 +6 ============================================ + Hits 28714 28733 +19 - Misses 40045 40050 +5 + Partials 2638 2637 -1 ```

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