Recommend App: Add Tracks

[dvdchr]

Refs #16995, pctCYC-8X-p2#comment-340
Depends on #17020

Summary

This adds tracking events in the ShareAppContentPresenter, with details as described in pctCYC-8X-p2#comment-340. Additionally, I updated TestAnalyticsTracker to store trackString calls (for unit testing purposes).

Note: I'll keep this PR in open until the middle of next week, in case if there are any feedback on the event names, etc.

To Test

There's no visual change, but tests for tracking verification is added. Make sure the tests are ✅ !

Regression Notes

1. Potential unintended areas of impact
   None.

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   Added unit tests for the tracking implementation.

3. What automated tests I added (or what prevented me from doing so)
   Added unit tests for the tracking implementation.

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

You can trigger optional UI/connected tests for these changes by visiting CircleCI here.

[peril-wordpress-mobile]

You can trigger an installable build for these changes by visiting CircleCI here.

[aerych]

Howdy @dvdchr 👋
Tested the events and confirmed they were dispatched as expected. For the failure event I confirmed by disabling wifi. Looks good!

[peril-wordpress-mobile]

	Warnings
⚠️	This PR is assigned to a milestone which is closing in less than 4 days Please, make sure to get it merged by then or assign it to a later expiring milestone

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[dvdchr]

Thank you!