L2SS-412: Actually await statistics_client.stop

devices/devices/sdp/statistics.py

@@ -101,7 +101,7 @@ class Statistics(opcua_device, metaclass=ABCMeta):
         """ user code here. is called when the state is set to OFF """
 
         try:
-            self.statistics_client.stop()
+            self.statistics_client.sync_stop()
         except Exception as e:
             logger.exception("Exception while stopping statistics_client in configure_for_off. Exception ignored")
 
@@ -134,7 +134,6 @@ class Statistics(opcua_device, metaclass=ABCMeta):
         _ = future.result()
 
     async def _connect_statistics(self):
-
         # map an access helper class
         for i in self.attr_list():
             try: