Wistar curtain: avoid use of state as an attribute name.

This is an undocumented value from the Tuya API.  Do not allow it to get
confused with the Home Assistant state.

Issue #320

custom_components/tuya_local/devices/wistar_roller_blind.yaml

@@ -42,7 +42,7 @@ primary_entity:
       name: curtain_hand
     - id: 106
       type: string
-      name: state
+      name: curtain_state
       mapping:
         - dps_val: "0"
           value: status_0