[Woo POS][Non-Simple Products] Handle empty state on variation screen

[AnirudhBhat]

Closes: #13206

Description

This PR

1. Handles empty variations state - Display proper empty screen similar to products when a variable product has no variations.
2. Modifies filter logic on products and variations screen so that variable product with no price set is displayed on products screen and variations that are disabled are not shown in variations screen.

Decision: pdfdoF-62l-p2#comment-7224

Steps to reproduce

Variable products with no variations published

1. Ensure you have a variable product with variations that are created but not published (Products screen > variation product > variations > disable variation)
2. Navigate to POS (more menu -> POS)
3. Ensure you see this variable product in the list
4. Ensure you see empty screen when opened

Variable products with no variations

1. Ensure you have a variable product with no variations created
2. Navigate to POS (more menu -> POS)
3. Ensure you see this variable product in the list
4. Ensure you see empty screen when opened

The tests that have been performed

Tested the above scenario by disabling variations both from the app and from the admin page.

Images/gif

variations_empty_state.mp4

• I have considered if this change warrants release notes and have added them to RELEASE-NOTES.txt if necessary. Use the "[Internal]" label for non-user-facing changes.

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	676af27
	Direct Download	woocommerce-wear-prototype-build-pr13209-676af27.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	676af27
	Direct Download	woocommerce-prototype-build-pr13209-676af27.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 6.45161% with 29 lines in your changes missing coverage. Please review.

Project coverage is 40.57%. Comparing base (d95c4a2) to head (676af27).
Report is 127 commits behind head on trunk.

Files with missing lines	Patch %	Lines
...ce/android/ui/woopos/home/items/WooPosItemsList.kt	0.00%	29 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk   #13209      +/-   ##
============================================
- Coverage     40.59%   40.57%   -0.02%     
- Complexity     6364     6365       +1     
============================================
  Files          1345     1345              
  Lines         77238    77267      +29     
  Branches      10601    10604       +3     
============================================
- Hits          31353    31350       -3     
- Misses        43128    43159      +31     
- Partials       2757     2758       +1     

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