PythonVirtualenvOperator: native template rendering breaks {{ ti }} / {{ task_instance }} pickling

### Description The PythonVirtualenvOperator docs state that passing/serializing `ti / task_instance` is not supported. However, I’m seeing a confusing behavior difference depending on `render_template_as_native_obj`: - With `render_template_as_native_obj=False`, templating `{{ ti }} / {{ task_instance }}` in `op_kwargs` appears to work (the task runs and prints values). - With `render_template_as_native_obj=True`, the task fails while serializing arguments for the subprocess with a `PicklingError` (non-obvious error mentioning loggers/structlog). **Minimal reproduction** ``` from pendulum import datetime from airflow.sdk import dag from airflow.providers.standard.operators.python import PythonVirtualenvOperator def venv_callable(ti, task_instance): print("ti =", ti) print("task_instance =", task_instance) @dag( start_date=datetime(2026, 1, 1), schedule=None, catchup=False, render_template_as_native_obj=False, # <-- changing only this flips behavior ) def test_simple(): PythonVirtualenvOperator( task_id="repro", python_callable=venv_callable, python_version="3.10", serializer="cloudpickle", op_kwargs={ "ti": "{{ ti }}", "task_instance": "{{ task_instance }}", }, requirements=["apache-airflow==3.1.6"], system_site_packages=False, ) test_simple() ``` **Steps to reproduce** - Run the DAG above with `render_template_as_native_obj=False` → task succeeds. - Change only `render_template_as_native_obj=True` → task fails during pickle/argument serialization. **Error / traceback (render_template_as_native_obj=True)** ``` [2026-01-29 23:06:37] INFO - Use 'cloudpickle' as serializer. [2026-01-29 23:06:37] ERROR - Task failed with exception PicklingError: Only BytesLoggers to sys.stdout and sys.stderr can be pickled. File "/home/airflow/.local/lib/python3.10/site-packages/airflow/sdk/execution_time/task_runner.py", line 1004 in run ... File "/home/airflow/.loc…