[ModelicaSystem] should not remove warnings as it is used by other functions

Author: syntron

OMPython/ModelicaSystem.py

@@ -45,6 +45,7 @@
 import tempfile
 import textwrap
 from typing import Any, Optional
+import warnings
 import xml.etree.ElementTree as ET
 
 from OMPython.OMCSession import OMCSessionException, OMCSessionZMQ, OMCProcessLocal