Merge branch 'am-add-test-level-to-json_formatter' into 'master'

Add test level to JsonFormatter

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/124456



Merged-by: David Dieulivol <ddieulivol@gitlab.com>
Approved-by: David Dieulivol <ddieulivol@gitlab.com>
Co-authored-by: Alina Mihaila <amihaila@gitlab.com>