Properties do not return anything

Fixes the docs-build job since the newest version of griffe is more strict about class properties.

The properties should not have a :returns: section. I fixed the two that had some and triggered the following warnings in CI

• https://gitlab.com/teklia/workers/base-worker/-/jobs/3466177846#L370
• https://gitlab.com/teklia/workers/base-worker/-/jobs/3466177846#L636

arkindex_worker/worker/base.py

@@ -153,7 +153,7 @@ class BaseWorker(object):
         """
         Whether or not the worker can publish data.
 
-        :returns: False when dev mode is enabled with the ``--dev`` CLI argument,
+        False when dev mode is enabled with the ``--dev`` CLI argument,
             when no worker run ID is provided
         """
         return self.args.dev or self.worker_run_id is None