Reader: Fix comments being misplaced after parent comment is moderated

[dvdchr]

Fixes #18081

This PR fixes the orphaned comments issue by "hiding" (or showing) the comment's replies after it is moderated. This follows the behavior on the web where the comment's thread is entirely hidden when it is not approved (or shown if it is).

Some implementation notes:

• I added visibleOnReader property on Comment to control whether the comment should be visible on the thread. This is because the comment thread is displayed with NSFetchedResultsController.
• The visibleOnReader property is assigned whenever the user visits the comment thread. Note that the screen downloads the comments every time the page is visited, so the value is guaranteed to be correct whenever the user visits the thread.
• Lastly, since comments can now be moderated directly from the thread, the comment's replies will be locally updated to have their visibility hidden or shown, matching the ancestor comment that's moderated.
  • Previously, the logic for the comment thread is we show all approved comments regardless of whether the parent/ancestor comment is unapproved/spammed/trashed.
• Additional note on why adding visibleOnReader instead of calling refreshAndSync after each moderation:
  • The behavior of refreshAndSync is that it downloads all comments and removes all the non-approved ones.
  • After moderating a comment, we offer an option for the user to undo the operation. If we call refreshAndSync after unapproving a comment, it will be deleted from Core Data and we'll have no way to undo the deletion of that one specific comment.

Also, I've noticed some additional issues in Reader Comments that is not addressed in this PR:

• While in the comment threads, I've noticed some warnings in the console related to cell prefetching:

  [Assert] UITableView internal inconsistency: prefetchedCells (5) and indexPathsForPrefetchedCells (6) are out of sync.
  

• The number of comments in Comments Snippet and in the Reader List may not match the actual number of comments displayed in the comment thread. The tricky part is the web also displays the same number... so this will need to be investigated separately.

To test:

Prepare a post with comments structured as described in #18081:

A
B
\__ C
     \__ D
E

Scenario 1: Moderating from Reader Comments

• Go to Reader Comments, and open the comment thread.
• Unapprove comment B by tapping on the contextual menu.
• 🔍 Verify comments B, C, and D are hidden.
• Tap the "Undo" button on the snack bar to revert the operation.
• 🔍 Verify that comments B, C, and D are now shown.

Scenario 2: Moderating from My Sites while the comment thread is opened

• Go to Reader Comments, and open the comment thread.
• Verify that you can see comments B, C, and D.
• Tap on the My Sites tab > Comments, and unapprove comment B.
• Go back to the Reader tab.
• 🔍 Verify comments B, C, and D are hidden.

Regression Notes

1. Potential unintended areas of impact
   Comments not being displayed correctly in the comment threads.

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   Manually tested the changes.

3. What automated tests I added (or what prevented me from doing so)
   N/A.

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]

	Warnings
⚠️	PR has more than 500 lines of code changing. Consider splitting into smaller PRs if possible.

Generated by 🚫 dangerJS

[wpmobilebot]

You can test the Jetpack changes on this Pull Request by downloading it from AppCenter here with build number: pr18094-7cd760d. IPA is available here. If you need access to this, you can ask a maintainer to add you.

[wpmobilebot]

You can test the WordPress changes on this Pull Request by downloading it from AppCenter here with build number: pr18094-7cd760d. IPA is available here. If you need access to this, you can ask a maintainer to add you.

[mokagio]

The build for the last commit failed because of a CI issue. I restarted it.

[ScoutHarris]

It'd be nice to add a release note. Otherwise 👍 .