Remove default Boil option for operation_mode.

> When I try to use the "Boil" work mode it just beeps a few times and nothing happens.

This may have been caused by the fact there were two "Boil" entries in the list,
and one had no linked "warm" value associated with it.

custom_components/tuya_local/devices/silvercrest_kettle.yaml

@@ -19,7 +19,6 @@ primary_entity:
               value: Keep warm
             - dps_val: false
               value: Boil
-            - value: Boil
     - id: 2
       type: integer
       name: current_temperature