text: Title: Occasional doc build failure  `example_debug_logging.py`
  Body: Occasional issue building docs with `example_single_configuration.py`
  
  Error:
  ```
  generating gallery for examples/40_advanced... [ 50%] example_debug_logging.py
  
  Warning, treated as error:
  /home/runner/work/auto-sklearn/auto-sklearn/examples/40_advanced/example_single_configuration.py failed to execute correctly: Traceback (most recent call last):
    File "/home/runner/work/auto-sklearn/auto-sklearn/examples/40_advanced/example_single_configuration.py", line 77, in <module>
      print(pipeline.named_steps)
  AttributeError: 'NoneType' object has no attribute 'named_steps'
  ```
  
  [Test log](https://github.com/automl/auto-sklearn/pull/1229/checks?check_run_id=3414079944)