Merge branch 'hm-threshold-for-parallel-gdk-jobs' into 'master'

Set threshold to 15 for parallel jobs

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/167113



Merged-by: Anastasia McDonald <amcdonald@gitlab.com>
Approved-by: Sofia Vistas <svistas@gitlab.com>
Approved-by: Anastasia McDonald <amcdonald@gitlab.com>
Reviewed-by: Anastasia McDonald <amcdonald@gitlab.com>
Co-authored-by: hmuralidhar <hmuralidhar@gitlab.com>