Replace gdk-qa-blocking and gdk-qa-non-blocking jobs with gdk-qa-instance

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/175218



Merged-by: Andrejs Cunskis <acunskis@gitlab.com>
Approved-by: Andrejs Cunskis <acunskis@gitlab.com>
Reviewed-by: Andrejs Cunskis <acunskis@gitlab.com>
Co-authored-by: Sanad Liaquat (Personal) <sliaquat@gitlab.com>