Remove spurious "SynapseRequest" result from `make_request"

tests/app/test_frontend_proxy.py

tests/app/test_openid_listener.py

tests/federation/test_complexity.py

tests/federation/test_federation_server.py

tests/federation/transport/test_server.py

tests/handlers/test_directory.py

tests/handlers/test_message.py

tests/handlers/test_password_providers.py

tests/handlers/test_typing.py

tests/handlers/test_user_directory.py

tests/http/test_additional_resource.py

tests/push/test_http.py

tests/replication/test_auth.py

tests/replication/test_client_reader_shard.py

tests/replication/test_multi_media_repo.py

tests/replication/test_sharded_event_persister.py

tests/rest/admin/test_admin.py

tests/rest/admin/test_device.py

tests/rest/admin/test_event_reports.py

tests/rest/admin/test_media.py