tasks: Simplify implementation and add tests for listed origins
Recent changes in swh-scheduler add new parameters to the celery tasks produced from swh.scheduler.model.ListedOrigin instances.
So ensure to handle any new parameters by not hardcoding the expected ones in task signatures.
Remove unsafe use of unnamed task parameters.
Add new tests checking task parameters produced from ListedOrigin instances do no raise error when attempting to create a bzr loader.
Related to swh-loader-core#4187 (closed)
Migrated from D7700 (view on Phabricator)