Fix repr for device created with no sysinfo or discovery info" (#1266)

Co-authored-by: Teemu R. <tpr@iki.fi>

kasa/smart/smartdevice.py

@@ -757,6 +757,10 @@ class SmartDevice(Device):
 
         # Fallback to device_type (from disco info)
         type_str = self._info.get("type", self._info.get("device_type"))
+
+        if not type_str:  # no update or discovery info
+            return self._device_type
+
         self._device_type = self._get_device_type_from_components(
             list(self._components.keys()), type_str
         )