L2SS-1258: Fix cleaning up event unsubscription maintenance

tangostationcontrol/tangostationcontrol/devices/temperature_manager.py

@@ -138,8 +138,12 @@ class TemperatureManager(LOFARDevice):
 
         # unsubscribe from all events
         for attr_name in list(self.temp_error_attrs.keys()):
+            try:
                 dev_attr = self.temp_error_attrs[attr_name]
                 dev_attr.proxy.unsubscribe_event(dev_attr.subscription_id)
+            except Exception as e:
+                raise Exception(f"Failed to unsubscribe from event regarding device {dev_attr.proxy.dev_name()} attribute {attr_name}") from e
+            finally:
                 del self.temp_error_attrs[attr_name]
 
     is_alarming_R = attribute(