sourceforge: Allow passing configuration arguments to task

The constructor allows it but not the celery task.

This also aligns the behavior with other lister tasks.

I'm trying to clean up a bit staging and list disabled origins in various listers [1]. In doing so, that one failed.

[1] In current staging, we are now often listing a subset of new forges to check the behavior (prior to actually deploying to production).

The old forges are still listing full pages though. Which makes that infra always running plenty of loaders. As the infra is a bit under load currently, and as it's not really needed nor sensible to always run those, i'm doing a bit of a clean up in that sense.