fixes line number copy issue for unfolded parallel view diff

What does this MR do?

Fixes #28367 (closed)

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

Why was this MR needed?

This MR fixes annoying line number included issue for unfolded diff.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Tests
  • All builds are passing
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #28367 (closed)