Backport removal of `"additionalProperties": false` runners schema
Problem to solve
In gitlab-org/gitlab-ee!7600 ee ci fails because of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7600#note_105310648 because we has "addtionalProperties" false
for conflict sake, we should remove it in ce as well
Further details
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7600#note_105324679
Proposal
Remove "additionalProperties": false