remove unused fixtures: use_api_[v1|v2]

Author: geetu040

tests/conftest.py

@@ -323,16 +323,6 @@ def workdir(tmp_path):
     os.chdir(original_cwd)
 
 
-@pytest.fixture
-def use_api_v1() -> None:
-    openml.config.set_api_version(api_version=APIVersion.V1)
-
-
-@pytest.fixture
-def use_api_v2() -> None:
-    openml.config.set_api_version(api_version=APIVersion.V2)
-
-
 @pytest.fixture
 def http_client_v1() -> HTTPClient:
     return HTTPClient(api_version=APIVersion.V1)