cannot import ipykernel debugger in Pycharm debug mode

when execute
```
import debugpy
from ipykernel.debugger import Debugger
```
in **pycharm debug mode**, result in `ImportError: cannot import name 'pydevd_defaults' from '_pydevd_bundle'`

and an more specfic notice is :

`/Users/suoyi/miniforge3/envs/aicoder/lib/python3.9/site-packages/debugpy/_vendored/force_pydevd.py:20: UserWarning: incompatible copy of pydevd already imported`

Reproduce the imports in PyCharm debug mode using the reported Python 3.9 environment, starting with debugpy/_vendored/force_pydevd.py and the ipykernel.debugger import. Trace the incompatible pydevd warning and ImportError; done means Debugger imports successfully in that mode without the pydevd_defaults failure.

Rédigé par le modèle d'indexation à partir du texte de l'issue.