fix(test): drop invalid None return type on generator fixture

Pyright rejects `-> None` on autouse fixtures that yield.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: ulises-jeremias

packages/create-awesome-python-app/tests/conftest.py

@@ -16,7 +16,7 @@
 
 
 @pytest.fixture(autouse=True)
-def _clean_cpa_process_env() -> None:
+def _clean_cpa_process_env():
     """Clear CPA env vars that CLI helpers set via ``os.environ`` (not monkeypatch).
 
     ``apply_fixture_mode`` mutates ``os.environ`` directly. Pairing that with