[GUI] Calib2 is not able to display detector with hexagonal pixels in 3D

[kif]

related to #1637

ERROR:pyFAI.gui.dialog.Detector3dDialog:Backtrace
Traceback (most recent call last):
  File "/home/kieffer/workspace-400/pyFAI/build/lib.linux-x86_64-3.9/pyFAI/gui/dialog/Detector3dDialog.py", line 94, in run
    result = self.runProcess()
  File "/home/kieffer/workspace-400/pyFAI/build/lib.linux-x86_64-3.9/pyFAI/gui/dialog/Detector3dDialog.py", line 106, in runProcess
    result = self.__createDetectorColormapMesh()
  File "/home/kieffer/workspace-400/pyFAI/build/lib.linux-x86_64-3.9/pyFAI/gui/dialog/Detector3dDialog.py", line 136, in __createDetectorColormapMesh
    values[0::4] = pixelValues
ValueError: could not broadcast input array from shape (243712) into shape (365568)