Remove redundant calls to `render()`

tests/app/test_frontend_proxy.py

tests/app/test_openid_listener.py

tests/http/test_additional_resource.py

tests/replication/_base.py

tests/replication/test_client_reader_shard.py

tests/replication/test_sharded_event_persister.py

tests/rest/client/test_consent.py

tests/rest/client/v1/utils.py

tests/rest/client/v2_alpha/test_sync.py

tests/server.py

tests/storage/test_client_ips.py

tests/test_server.py

tests/unittest.py