We should add line numbers to the message display ([this view](https://mastercard.github.io/flow/execution/latest/app-itest/target/mctf/latest/detail/7E22263CB3957E4841C81B8933D5CB47.html#?msg=5)). The line numbers should _not_ be drag-selectable - copy how the diff ([this view](https://mastercard.github.io/flow/execution/latest/app-itest/target/mctf/latest/detail/7E22263CB3957E4841C81B8933D5CB47.html#?msg=5&display=Diff)) does it.
