Cancel run

Stop a run that is still going: one run_pipeline, assemble_video or edit_asset started. Use it when the person asks to cancel, stop or kill a render, including "stop, that's wrong" about one they can see running. A render that is rendering stops once its current step finishes (status "cancelling", then "cancelled" in get_run); one still waiting to start is closed at once and costs nothing. Steps that already finished keep their output and are not refunded. Leave out runId to cancel the pipeline's newest running run. Needs the pipelines:run scope.