Unauthenticated uploads (e.g. via source) do not trigger `job-done` event

If I upload an item via a source, no `job-done` notification event is triggered.

Looking at debug/trace logs, the following appears curious:

```
docspell.store.impl.DoobieMeta - SQL: Success(SELECT c.id, c.name, u.uid, u.login, u.password, c.state, u.state, u.account_source FROM user_ u INNER JOIN collective c ON u.coll_id = c.id WHERE (c.id = ? AND u.login = c.name),List(CollectiveId(1)),804277 nanoseconds,80443 nanoseconds)

docspell.scheduler.impl.SchedulerImpl.makeJobDoneEvent:246 - Found job owner None for job RJob(Ident(EmTTECm8YB2-WD8wSCfMvoq-pTzQr3wBozp-KXwPAq9Esjq),Ident(process-item),Ident(1),{"meta":{"collective":1,"itemId": …
```

There is no job owner, unless maybe the username and collective are the same (cf. the SQL). I have not tested that, but I did verify that the even fires just fine as soon as I do an upload via `sec/upload/item` instead.