Crash when closing a plot

[MialLewis]

Describe the bug When closing a plot during beta testing, mslice crashed. Didn't catch what type of plot it was.

In involved loading data, so I suspect it's something to do with closing an interactive cut, from a slice plot that has been deleted.

Stack trace as follows:

  File "/opt/mantidworkbenchnightly/scripts/ExternalInterfaces/mslice/plotting/plot_window/plot_window.py", line 46, in closeEvent
    self.canvas.manager.window_closing()
  File "/opt/mantidworkbenchnightly/lib/python3.10/site-packages/mantidqt/utils/qt/qappthreadcall.py", line 69, in __call__
    return self._callable(*args)
  File "/opt/mantidworkbenchnightly/scripts/ExternalInterfaces/mslice/plotting/plot_window/plot_figure_manager.py", line 76, in window_closing
    self.plot_handler.window_closing()
  File "/opt/mantidworkbenchnightly/scripts/ExternalInterfaces/mslice/plotting/plot_window/cut_plot.py", line 146, in window_closing
    icut.window_closing()
  File "/opt/mantidworkbenchnightly/scripts/ExternalInterfaces/mslice/plotting/plot_window/interactive_cut.py", line 118, in window_closing
    self.slice_plot.toggle_interactive_cuts()
  File "/opt/mantidworkbenchnightly/scripts/ExternalInterfaces/mslice/plotting/plot_window/slice_plot.py", line 397, in toggle_interactive_cuts
    self.toggle_icut_button()
  File "/opt/mantidworkbenchnightly/scripts/ExternalInterfaces/mslice/plotting/plot_window/slice_plot.py", line 403, in toggle_icut_button
    if self.plot_window.action_zoom_in.isChecked():
RuntimeError: wrapped C/C++ object of type QAction has been deleted
        Using: workbench 6.7.20230925.1341 on CentOS Linux 7 (Core)

[SilkeSchomann]

I have tried to reproduce this with slice and cut plots, as well as interactive cuts. As the stack trace mentions zoom in, I have also zoomed in on various plots and then deleted the underlying workspace. I am closing the issue now as it was impossible to reproduce this.