ert vis doesn't work with Python 3.11

[kvashchuka]

Describe the bug
Running ert vis poly.ert (on mac) with Python 3.11 crashes with "Cannot connect to localhost" error in the browser. It is working with Python 3.10. Tested on Firefox and Chrome

To reproduce
Steps to reproduce the behaviour:

1. Create a python environment with Python 3.11 version
2. pip install ert
3. ert vis my_config.ert
4. Browser will open with the message Firefox can’t establish a connection to the server at localhost:5001.

Expected behaviour
It shouldn't crush

[larsevj]

The following exception is also printed to the console:

[oysteoh]

Duplicated by github.com/equinor/scout/issues/936