PR: Fix callable associated to restart_action (IPython console)

[ccordoba12]

Description of Changes

• This was a regression introduced by PR: Make Matplotlib status bar widget show the right backend and fix some errors related to kernel restarts for options that require them #22057.
• Also, expand test suite to check that action is working as expected.

Issue(s) Resolved

Fixes #22084

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[dalthviz]

Thanks @ccordoba12 ! Checked locally and seems like things are now working as expected for the restart kernel action 👍 However, seems like now a test related with the interactive backend is failing (https://github.com/spyder-ide/spyder/actions/runs/9105002468/job/25052184772?pr=22085#step:15:5891)?

Currently trying to check locally what could be causing that but seems like the failing test is marked as not meant to be run on Windows 🤔

[ccordoba12]

However, seems like now a test related with the interactive backend is failing

Yep, I think that's caused by the release of Matplotlib 3.9, which was done yesterday. Since it's not available yet in Conda-forge (see conda-forge/matplotlib-feedstock#373), it won't affect our installers.

If we want to release 6.0 final in June, I think it's best to release beta1 now with this small error and fix it in beta2, which should be ready in two weeks at most.