I was not able to find a way to enable it inside the pipeline itself even if I really wished it was.
Now we have it enabled in JJB job definitions, which in our case, is also using DSL/pipeline. Mainly this means that we enable it outside the pipeline. We do the same things with many other things include the job parameters because defining them into pipeline works only after you get a successful execution of the job, which is bit stupid and incompatible with our use cases.
Maybe someone will find a way, I am watching this ticket.