Sort updated comments chronoligically

Description / Overview

Sort comments by updated field and fix visibility

Use cases

When two people submit comments on a feedback and try to edit them afterwards, the history is not chronological. We need chronological order for better visualisation. Also, the visibility is not updated when a comment was updated.

Feature checklist

• Make the backend include updated field for feedback comments
• Fix visibility not updating for already existing comments

(Make sure these are completed before closing the issue, with a link to the relevant commit.)