[OMCProcess] fix Python < 3.12

Author: syntron

OMPython/OMCSession.py

@@ -769,7 +769,7 @@ def omcpath(self, *path) -> OMCPath:
 
         # fallback solution for Python < 3.12; a modified pathlib.Path object is used as OMCPath replacement
         if sys.version_info < (3, 12):
-            if isinstance(self._omc_process, OMCProcessLocal):
+            if isinstance(self, OMCProcessLocal):
                 # noinspection PyArgumentList
                 return OMCPath(*path)
             raise OMCProcessException("OMCPath is supported for Python < 3.12 only if OMCProcessLocal is used!")