Fix run time errors with python3.12 and pyside6 (#13337)

* Change pyopen=open expression to from builtins import open as pyopen

---------

Co-authored-by: Adrián Insaurralde Avalos <36372335+adrianinsaval@users.noreply.github.com>

src/Mod/CAM/Path/Post/scripts/example_pre.py

@@ -35,6 +35,7 @@ from GCode.
 import FreeCAD
 import Path
 import os
+from builtins import open as pyopen
 
 # LEVEL = Path.Log.Level.DEBUG
 LEVEL = Path.Log.Level.INFO
@@ -44,9 +45,7 @@ if LEVEL == Path.Log.Level.DEBUG:
     Path.Log.trackModule(Path.Log.thisModule())
 
 
-# to distinguish python built-in open function from the one declared below
-if open.__module__ in ["__builtin__", "io"]:
-    pythonopen = open
+
 
 
 def open(filename):
@@ -60,7 +59,7 @@ def open(filename):
 def insert(filename, docname):
     "called when freecad imports a file"
     Path.Log.track(filename)
-    gfile = pythonopen(filename)
+    gfile = pyopen(filename)
     gcode = gfile.read()
     gfile.close()
     gcode = parse(gcode)