Enable KNX auto_reconnect for auto-discovered connections (#46178)

homeassistant/components/knx/__init__.py

@@ -290,7 +290,7 @@ class KNXModule:
         if CONF_KNX_ROUTING in self.config[DOMAIN]:
             return self.connection_config_routing()
         # config from xknx.yaml always has priority later on
-        return ConnectionConfig()
+        return ConnectionConfig(auto_reconnect=True)
 
     def connection_config_routing(self):
         """Return the connection_config if routing is configured."""