[BUG] Jupyter jupyter_dash.infer_jupyter_proxy_config() doesn't work with ipykernel>=7

[AlexCK-STFC]

Describe your context

dash                      4.2.0
ipykernel               7.3.0

Describe the bug

Docs say to use:

from dash import jupyter_dash

jupyter_dash.infer_jupyter_proxy_config()

to determine proxy configuration.

But this method no longer seems to exist in ipykernel:

AttributeError                            Traceback (most recent call last)
Cell In[1], line 3
      1 from dash import jupyter_dash
      2 
----> 3 jupyter_dash.infer_jupyter_proxy_config()

File /opt/conda/lib/python3.13/site-packages/dash/_jupyter.py:266, in JupyterDash.infer_jupyter_proxy_config(self)
    264     return
    265 # Assume classic notebook or JupyterLab
--> 266 _request_jupyter_config()

File /opt/conda/lib/python3.13/site-packages/dash/_jupyter.py:205, in _request_jupyter_config(timeout)
    202 if _jupyter_comm_response_received():
    203     break
--> 205 if inspect.iscoroutinefunction(kernel.do_one_iteration):
    206     loop = asyncio.get_event_loop()
    207     nest_asyncio.apply(loop)

AttributeError: 'IPythonKernel' object has no attribute 'do_one_iteration'