Inconsistent error when closing sliceviewer

[MialLewis]

Describe the bug
During manual testing of 6.12 release-next nightly, the following error message was seen when closing sliceviewer:

Traceback (most recent call last):  File "/opt/mantidworkbenchnightly/lib/python3.10/site-packages/matplotlib/cbook.py", line 298, in process    func(*args, **kwargs)  File "/opt/mantidworkbenchnightly/lib/python3.10/site-packages/mantidqt/widgets/sliceviewer/views/cursor.py", line 57, in on_mouse_leave    self.on_cursor_outside_axes()  File "/opt/mantidworkbenchnightly/lib/python3.10/site-packages/mantidqt/widgets/sliceviewer/presenters/imageinfowidget.py", line 67, in on_cursor_outside_axes    self._widget.cursorAt(DBLMAX, DBLMAX, DBLMAX, extra_cols)RuntimeError: wrapped C/C++ object of type ImageInfoWidget has been deleted

This occurs inconsistently, though was replicated on both IDAaaS and OSX.

s(q,w) portion of https://developer.mantidproject.org/Testing/Inelastic/QENSFittingTests.html

[sf1919]

Is this a regression?