Zombie dotnet-iqsharp kernel processes after IPython kernel restart

[xinyi-joffre]

Describe the bug
The underlying IQ# kernel spun up behind the scenes of the IPython kernel are not always cleaned up when the IPython kernel is restarted or shutdown.

To Reproduce
Steps to reproduce the behavior:

1. Open notebook with IPython kernel
2. Run import qsharp
3. Restart the kernel and maybe repeat 2-3 a few times
4. Check running processes on either Windows or Linux, and see that there are zombie dotnet-iqsharp processes leftover from the kernel that was restarted.

The good thing is that when the notebook server is shutdown, then all child processes are cleaned up correctly.

Expected behavior
There should only be one dotnet-iqsharp process per IPython kernel where import qsharp is run. After killing the IPython kernel, the dotnet-iqsharp process should also be killed.

Screenshots
On windows:

On linux:

System information

• OS: [e.g. iOS] Windows + Ubuntu Container
• Browser [e.g. chrome, safari] N/A
• Version [e.g. 22] QDK + qsharp python package version: 0.23.195983

Additional context
This seems possibly related to the issues that were fixed in ipykernel recently:
ipython/ipykernel#869 (27 days ago)
ipython/ipykernel#874 (24 days ago)

But I installed the latest 6.9.2 of ipykernel, and these issues did not resolve.