[Woo POS][Non Simple Products] Checkout variations

[AnirudhBhat]

Closes: #12925

Description

This PR supports check out of the variations successfully. With this PR, you should be able to select, add, and then checkout variations successfully on POS mode.

Testing information

Try selecting different variations, add those to the cart, and then proceed to checkout and complete the transaction. It should finish successfully and you should be able to see all the products correctly in the order detail screen.

The tests that have been performed

Checkout successfully

1. Navigate to the POS mode (more menu -> POS)
2. Select any variable product from the items list
3. Ensure you navigate to the variations list screen
4. Select any variations
5. Ensure those gets added to the cart
6. Proceed to checkout
7. Ensure the transaction completes successfully

Correct product details in Order details screen

1. Navigate to the POS mode (more menu -> POS)
2. Select any variable product from the items list
3. Ensure you navigate to the variations list screen
4. Select any variations
5. Ensure those gets added to the cart
6. Proceed to checkout
7. Ensure the transaction completes successfully
8. Exit POS and come back to the orders tab
9. Select the order that just got created
10. Ensure you see all the products (variations) you added there and are correct

Images/gif

https://github.com/user-attachments/assets/a4314047-ac5b-4f76-ba19-c673dba22041

• [x] 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	679b6a1872a6343f71dbcbbb3daea32cb12f3958
	Direct Download	woocommerce-wear-prototype-build-pr12927-679b6a1.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	679b6a1872a6343f71dbcbbb3daea32cb12f3958
	Direct Download	woocommerce-prototype-build-pr12927-679b6a1.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 69.07216% with 30 lines in your changes missing coverage. Please review.

Project coverage is 39.61%. Comparing base (dc04809) to head (6e70393).

Files with missing lines	Patch %	Lines
...id/ui/woopos/home/totals/WooPosTotalsRepository.kt	58.49%	17 Missing and 5 partials :warning:
...android/ui/woopos/home/cart/WooPosCartViewModel.kt	78.26%	3 Missing and 2 partials :warning:
...rce/android/ui/woopos/home/cart/WooPosCartState.kt	75.00%	2 Missing :warning:
...oid/ui/woopos/home/totals/WooPosTotalsViewModel.kt	80.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## issue/12845-add-variation-to-cart #12927 +/- ## ==================================================================== Coverage 39.60% 39.61% - Complexity 5961 5969 +8 ==================================================================== Files 1268 1268 Lines 73215 73270 +55 Branches 10050 10055 +5 ==================================================================== + Hits 29000 29027 +27 - Misses 41635 41659 +24 - Partials 2580 2584 +4 ```

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[wpmobilebot]

Version 21.2 has now entered code-freeze, so the milestone of this PR has been updated to 21.3.