Exception opening new comm: make that message more relevant (or silence it altogether)

[parmentelat]

I have one repo that comes with quite a few notebooks; when running myst on that repo the logs get totally clobbered with a message that says

Exception opening new comm

so many times that the noise makes it almost impossible to get the signal out of the logs

Proposal

if that message is truly helpful, make it more explicit; otherwise silence it down or lower its importance so a regular run does not show them at all

Additional notes

this GH action run gives an example of what I mean

https://github.com/flotpython/course/actions/runs/18749888419/job/53487940513