[Product AI] Make requests in parallel when saving the product

[hichamboushaba]

Closes: #12664

Description

This PR updates the logic of saving the AI generated product as draft to make the preparation requests in parallel, this should speed up the process, and it's how iOS is handling it.

To make the upload request also in parallel, I moved it to the usecase SaveAiGeneratedProduct, which required some changes to the ViewModel too.

From my tests, with this change, the saving (including image upload) was reduced from 12 seconds to 7 seconds in my test website.

Steps to reproduce

1. Open the app.
2. Navigate to the Products tab.
3. Start product creation and select AI creation.
4. Complete the flow.

Testing information

• Test creation when having an image.
• Test creation without image.

The tests that have been performed

^

Images/gif

• 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.

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 20.8. 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 🚫 Danger

[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	efb4286
	Direct Download	woocommerce-wear-prototype-build-pr12770-efb4286.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	efb4286
	Direct Download	woocommerce-prototype-build-pr12770-efb4286.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 24.61538% with 49 lines in your changes missing coverage. Please review.

Project coverage is 40.84%. Comparing base (5a9dbdd) to head (efb4286).
Report is 115 commits behind head on trunk.

Files with missing lines	Patch %	Lines
...e/android/ui/products/ai/SaveAiGeneratedProduct.kt	4.00%	48 Missing ⚠️
...i/products/ai/preview/AiProductPreviewViewModel.kt	93.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk   #12770      +/-   ##
============================================
- Coverage     40.86%   40.84%   -0.02%     
+ Complexity     5757     5752       -5     
============================================
  Files          1236     1236              
  Lines         69722    69738      +16     
  Branches       9668     9673       +5     
============================================
- Hits          28490    28486       -4     
- Misses        38604    38624      +20     
  Partials       2628     2628              

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[JorgeMucientes]

Great job @hichamboushaba code changes look great and everything is still working as expected. I didn't notice such a big improvement in the the time taken to save the product as you experienced on your site, but still I could see like 2-3 secs improvement on my tests. In any case the changes make sense and code is cleaner and more optimized now.

[JorgeMucientes]

Nice 💯