Resolve "Line numbers are off in dynamically loaded diff chunks"

What does this MR do?

Fixes line number rendering error on dynamically loaded diff chunks.

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

Best way to test this is to visit the following MR in your GDK: http://localhost:3000/gitlab-org/gitlab-test/merge_requests/9/diffs (if your MR ids are different, this is the "Cannot be automatically merged" MR within the Gitlab Test project)

Check the file files/ruby/regex.rb file and click the diff unfolding links at the bottom of the file (make sure to do this twice - the second ellipsis generated after unfolding the first time actually gets rendered by a different view file and it needs to be tested as well)

Do the same for both parallel and inline diff views (these are also separate view files)

Screenshots (if relevant)

Before unfolding:

Before (incorrect line numbers):

After (correct line numbers):

Does this MR meet the acceptance criteria?

• Changelog entry added
• Tests
  • Added for this feature/bug
  • All builds are passing
• 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 #26300 (closed)