tools/patchwork_gitlab_igt: Ask API just for the failed jobs
The default behavior of GitLab's API endpoints is to get only 20 objects per page[0].
We are hitting this limit when getting jobs for a failed pipeline (we are just slightly above 20 jobs as of this patch), which may results in us not providing the failure context/details in the patchwork email.
To fix that we can ask the endpoint to get us just the failed jobs[1].
If we get more than 20 failed jobs we don't want to publish all of that anyway - it's already obvious that things are broken.
[0]: https://docs.gitlab.com/ce/api/README.html#pagination
[1]: https://docs.gitlab.com/ce/api/jobs.html#list-pipeline-jobs