In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/31731 we are
displaying the import status to the user. We need to be able to show the
user that an import has been scheduled. As this happens asynchronously,
the running of the job will likely happen after the request returns to
the client.

Currently our group import state is created in the job, but we need to
create it before the job is triggered so that we can have an in progress
import state when we return the HTTP request. If we create the import
state after scheduling the job, we end up with a race condition between
the job wanting to use the import state and the import state being
created in the request.

For this reason, we remove the requirement for the jid to be present.
This also follows the same pattern that the ProjectImportState takes.
This will also mean that if we fail to schedule an import job (no jid is
returned) we can still mark the import as failed properly.

MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/33181
Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/211808