feat (weeket_kettle): support KE4071TB variant

- need to make mode optional (at least when power is off)

Issue #4290

custom_components/tuya_local/devices/weeket_kettle.yaml

@@ -3,6 +3,9 @@ products:
   - id: 01rtpfyd3amxdsps
     manufacturer: Weekett
     model: KE4071TF
+  - id: n9c9gxaavafz3fii
+    manufacturer: Weekett
+    model: KR4071TB
 entities:
   - entity: water_heater
     translation_key: kettle
@@ -61,6 +64,7 @@ entities:
     dps:
       - id: 16
         type: string
+        optional: true
         name: option
         mapping:
           - dps_val: setting_quick