Include FOSS on security sync service
What does this MR do?
Includes GitLab FOSS on Security::SyncRemoteService
One of the last steps on a security release is to sync the branches among remotes. Initially, we assumed GitLab FOSS was automatically synced by merge train, but it appears that is not the case.
This commits includes FOSS on the SyncRemoteService, so it's automatically synced when a Release Manager triggers the sync_remotes task.
Related to https://gitlab.com/gitlab-org/release-tools/-/issues/450