wxpython 4.3.x compatibility for DisplayOptionsPanel.py - #1690

Traceback (most recent call last):
  File "/Users/andy/miniconda3/envs/wx4p3/lib/python3.12/site-packages/wx/core.py", line 3429, in <lambda>
    lambda event: event.callable(*event.args, **event.kw) )
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/andy/code/python-microscopy/PYME/DSView/dsviewer.py", line 475, in LoadData
    vframe = DSViewFrame(im, None, im.filename, mode = mode)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/andy/code/python-microscopy/PYME/DSView/dsviewer.py", line 161, in __init__
    self.optionspanel = OptionsPanel(self, self.do, thresholdControls=True)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/andy/code/python-microscopy/PYME/DSView/DisplayOptionsPanel.py", line 218, in __init__
    ssizer.Add(self.cbShowThreshold, 0, wx.ALL, 5)
wx._core.wxAssertionError: C++ assertion "Assert failure" failed at ./src/common/datetime.cpp(295) in wxCallStrftime(): strftime() failed