Resolve "Merge conflict resolution removed the newline in the end of file"

What does this MR do?

Add a newline back to the created file when resolving conflicts by picking sides, if our side of the conflict has a trailing newline.

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

Don't think so!

Why was this MR needed?

This was a silly bug.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• 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 #32983 (closed).