Remove non-compact version of dataset list api

[fm3]

https://github.com/scalableminds/webknossos/pull/6834 introduces a new compact version of the dataset list api. The front-end only uses that one. The libs also don’t rely on the old version of the route having more fields than what compact now includes. Thus, we should unify the two routes (i.e. use the compact code and return value always, remove the argument)

[fm3]

Before changing this in the backend, we should double-check that the libs can really work also with the compact variant. I’m not so sure about that anymore. For example, https://github.com/scalableminds/webknossos-libs/blob/f40e4a65ee1a19a58db097eb6f9be157c7cef465/webknossos/webknossos/client/api_client/models.py#L71 seems to expect a dataSource property.

So instead maybe we should introduce a new API version with backwards compatibility adapters for the non-compact variant.

However, I’d say we should not do that while #7783 is in progress, since that also introduces a new API version that interfaces with the dataset routes. Moving this back to backlog for the moment.