Force default ordering for API

src/representatives/api.py

...ixtures/RepresentativeManagerTest.test_groups_api.content

...tures/RepresentativeManagerTest.test_mandates_api.content

...epresentativeManagerTest.test_representatives_api.content

src/representatives_recommendations/api.py

src/representatives_votes/api.py

..._fixtures/RepresentativeManagerTest.test_proposal.content

...nse_fixtures/RepresentativeManagerTest.test_votes.content