Do not send light_on value to iot bulb set_state (#1090)

Passing this extra value caused the `ignore_default` check in the `IotBulb._set_light_state`
method to fail which causes the device to come back on to the default state.

kasa/iot/iotbulb.py

@@ -326,6 +326,7 @@ class IotBulb(IotDevice):
         self, state: dict, *, transition: int | None = None
     ) -> dict:
         """Set the light state."""
+        state = {**state}
         if transition is not None:
             state["transition_period"] = transition