Add feature flag for non-simple product types project

[AnirudhBhat]

Closes: #12807

Description

This PR adds a feature flag so that we could remove the "Simple" products filter for the products api and start showing all different product types for POS. This would help us in development of supporting Variable products for POS.

Testing information

Unit tests have been added to ensure this change doesn't break anything.

The tests that have been performed

1. Unit tests for testing that both enabling and disabling the feature flag works as expected.
2. Create a release build and ensure you don't see Variable products on POS. In other words, you should only see Simple products only on POS.
3. Create a Debug build and ensure you see all products on POS.

• 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	6a260b9
	Direct Download	woocommerce-wear-prototype-build-pr12811-6a260b9.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	6a260b9
	Direct Download	woocommerce-prototype-build-pr12811-6a260b9.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 84.61538% with 2 lines in your changes missing coverage. Please review.

Project coverage is 40.86%. Comparing base (e1ef2aa) to head (6a260b9).
Report is 121 commits behind head on trunk.

Files with missing lines	Patch %	Lines
...pos/featureflags/IsNonSimpleProductTypesEnabled.kt	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##              trunk   #12811   +/-   ##
=========================================
  Coverage     40.86%   40.86%           
  Complexity     5765     5765           
=========================================
  Files          1237     1238    +1     
  Lines         69857    69864    +7     
  Branches       9707     9708    +1     
=========================================
+ Hits          28545    28550    +5     
- Misses        38677    38679    +2     
  Partials       2635     2635           

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[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 21.1. This milestone is due in less than 2 days. Please make sure to get it merged by then or assign it to a milestone with a later deadline.

Generated by 🚫 Danger

[samiuelson]

LGTM!