[AirPlaneDesign] Python 3.11.x and above Json Fix for FreeCAD 0.21.2 …

[Syres916]

…and above

In order to fix errors using Python 3.11.x and above while preserving ability for Python 3.10.x and below to still work correctly, example error from another workbench:

  File "/usr/lib/python3.11/json/encoder.py", line 180, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
<class 'TypeError'>: Object of type FeaturePython is not JSON serializable
17:04:02  PropertyPythonObject::toString(): failed for <class 'SheetMetalCmd.SMViewProviderFlat'>
17:04:02  pyException: Traceback (most recent call last):
  File "/usr/lib/python3.11/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/json/encoder.py", line 200, in encode
    chunks = self.iterencode(o, _one_shot=True)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/json/encoder.py", line 258, in iterencode
    return _iterencode(o, 0)
           ^^^^^^^^^^^^^^^^^

Root Cause is https://github.com/FreeCAD/FreeCAD/commit/fbe2fef

Note: I am trying to contact the owner of CurvedShapes Wb as it's a dependency and therefore must be changed as well otherwise it's likely to still fail on saving the file.