fix for auto labeler (#88100)
followed https://lightrun.com/answers/actions-labeler-how-to-only-add-label-not-remove-when-pr-is-opened
side note: should we move this logic to test-infra to be with the release notes labeler?
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88100
Approved by: https://github.com/huydhn
