Comment 1 for bug 2034027

Verified in staging that indeed when calling `setCommentVisibility(1)` (both via API and using the UI) in the example bug above, comment #3 is the one being updated.

I drafted a quick test to verify that the issue happens when the date when the comments were created don't match their index order. When we fetch the comment to set its visibility, we get the list of comments ordered by date, and then simply get the n-th comment.

This bug should only happen in very rare cases.