[Woo POS] Improve POS tracking conformance

[iamgabrielma]

Closes: #15149

Description

This PR improves conformance by splitting POS-related events from shared CollectOrderPaymentAnalyticsTracking protocol to a separate POSCollectOrderPaymentAnalyticsTracking protocol, which holds the POS-specific functions, clearing up the shared protocol to have empty implementations.

Changes

• Create a POSCollectOrderPaymentAnalyticsTracking protocol that contains POS-related events
• Make a new POSCollectOrderPaymentAnalytics, that conforms to POSCollectOrderPaymentAnalyticsTracking
• Make a new MockPOSCollectOrderPaymentAnalytics for tests
• Inject the specific dependency into POS

Testing information

• There are no functional changes. CI should pass.

Question:

When updating the test with the new mock, I've realized the test removeAllItemsFromCart_when_tapped_then_tracks_event fails. This is expected since we've updated this functionality on #15200 , however, CI never failed and we could merge this normally. I've removed the test in this PR but I'm wondering if there are differences we should be aware off in POS (eg: iOS17?)

---

• 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:

• 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 all devices (phone/tablet) and no regressions are added.

[dangermattic]

	2 Warnings
⚠️	View files have been modified, but no screenshot or video is included in the pull request. Consider adding some for clarity.
⚠️	This PR is assigned to the milestone 21.8. 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.

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[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS
	Build Number	pr15214-33b40e9
	Version	21.7
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	33b40e9
	App Center Build	WooCommerce - Prototype Builds #13068

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[staskus]

Looks good!