[ModelicaSystem] replace ET.parse() with ET.ElementTree(ET.fromstring())

read the file content and work on this string

see: https://stackoverflow.com/questions/647071/python-xml-elementtree-from-a-string-source

Author: syntron

OMPython/ModelicaSystem.py

@@ -514,7 +514,8 @@ def _xmlparse(self, xml_file: pathlib.Path):
         if not xml_file.is_file():
             raise ModelicaSystemError(f"XML file not generated: {xml_file}")
 
-        tree = ET.parse(xml_file)
+        xml_content = xml_file.read_text()
+        tree = ET.ElementTree(ET.fromstring(xml_content))
         rootCQ = tree.getroot()
         for attr in rootCQ.iter('DefaultExperiment'):
             for key in ("startTime", "stopTime", "stepSize", "tolerance",