[OMCSession] fix definiton of _timeout variable - use set_timeout() checks

Author: syntron

OMPython/OMCSession.py

@@ -648,7 +648,9 @@ def __init__(
         """
 
         # store variables
-        self._timeout = timeout
+        # set_timeout() is used to define the value of _timeout as it includes additional checks
+        self._timeout: float
+        self.set_timeout(timeout=timeout)
         # generate a random string for this instance of OMC
         self._random_string = uuid.uuid4().hex
         # get a temporary directory