Broken parsing for Koji builds with other method than 'build'

[sentry-io]

Sentry Issue: PCKT-002-PACKIT-SERVICE-7D1

ValueError: too many values to unpack (expected 3)
(2 additional frame(s) were not displayed)
...
  File "celery/app/task.py", line 736, in retry
    raise_with_context(exc)
  File "celery/app/autoretry.py", line 38, in run
    return task._orig_run(*args, **kwargs)
  File "packit_service/worker/tasks.py", line 180, in process_message
    return SteveJobs.process_message(event=event, source=source, event_type=event_type)
  File "packit_service/worker/jobs.py", line 173, in process_message
    event_object: Optional[Event] = parser(event)
  File "packit_service/worker/parser.py", line 1367, in parse_koji_build_event
    raw_git_ref, fedora_target, _ = event.get("request")