Fix diff comments inverted toggle bug

What does this MR do?

Explicitly set the comments visibility toggle based on the active css class.

Are there points in the code the reviewer needs to double check?

Shouldn't be

Why was this MR needed?

Fixes existing UI bug

What are the relevant issue numbers?

Closes #20898 (closed)

Screenshots (if relevant)

Before:

After:

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Tests
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together