SmartplugV2 Energy: make "initial state" optional.

To match SWE SAGEWE F2s501-GB

Replaces PR #1094

custom_components/tuya_local/devices/smartplugv2_energy.yaml

@@ -6,6 +6,8 @@ products:
     name: Antela ZY-OYD-Y
   - id: qiv5hllylfebpl4g
     name: Eightree ET20
+  - id: 7k5zwdhwlnrtsuhu
+    name: SWE SAGEWE F2s501-GB
 primary_entity:
   entity: switch
   class: outlet
@@ -125,6 +127,7 @@ secondary_entities:
       - id: 38
         type: string
         name: option
+        optional: true
         mapping:
           - dps_val: "on"
             value: "On"