Jupyter console broken

[thomashampson]

Describe the bug
Jupyter console does not seem to be working very well on recent Conda installs (including on IDAaaS). Trying to run anything at all results in this kind of error:

        Stack Trace:
        Traceback (most recent call last):
  File "/opt/mantidworkbench6.6/lib/python3.8/site-packages/qtconsole/base_frontend_mixin.py", line 138, in _dispatch
    handler(msg)
  File "/opt/mantidworkbench6.6/lib/python3.8/site-packages/qtconsole/jupyter_widget.py", line 193, in _handle_execute_reply
    super()._handle_execute_reply(msg)
  File "/opt/mantidworkbench6.6/lib/python3.8/site-packages/qtconsole/frontend_widget.py", line 468, in _handle_execute_reply
    if not self.kernel_client.iopub_channel.closed():
AttributeError: 'QtInProcessChannel' object has no attribute 'closed'

Afterwards it is completely unuseable.

I have narrowed this down to an upgrade of our qtconsole dependency. It seems to have broken with v5.4.2, I think due to this PR:
jupyter/qtconsole#574

To Reproduce

1. Install mantidworkbench into a new Conda environment.
2. Type anything (e.g. i = 1) into the Jupyter console and press return. It will pop up the error reporter.

Expected behavior
It should work.

Platform/Version (please complete the following information):

• OS: Any
• Mantid Version: any installed from Conda with qtconsole==5.4.2

Additional context
This will likely be fixed by this open PR in the qtconsole repo jupyter/qtconsole#575 but in the meantime we should pin to 5.4.1 so that the nightly version works.

[peterfpeterson]

@zjmorgan pointed this out at ORNL as well.

Notes from @AndreiSavici is that v6.6 vs nightly are using

v6.6: Jupyter QtConsole 5.4.0, IPython 8.11.0.
In nightly: Jupyter QtConsole 5.4.2, IPython 8.12.0

The bug that exists in v5.4.2 is fixed in this PR