Resolve "Comment appears in a wrong place after changing diff view to inline"

What does this MR do?

Fixes diff commenting results when you changed your diff view in this request.

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

I thought about a feature spec, but that seems very heavy for this case.

Why was this MR needed?

It was a (probably very old) bug!

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests
  • Added for this feature/bug
  • All builds are passing
• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #35695 (closed).