Kogan bidet: make position optional. Add seated sensor.

DP 55 is missing in some logs, preventing the device from being detected.
DP 46 can be seen in some of these logs, it was left out originally because it did not seem to be implemented.

Issue #559

custom_components/tuya_local/devices/kogan_bidet.yaml

@@ -82,6 +82,7 @@ secondary_entities:
       - id: 55
         type: string
         name: option
+        optional: true
         mapping:
           - dps_val: pos_1
             value: Front
@@ -98,7 +99,7 @@ secondary_entities:
     category: config
     icon: "mdi:car-seat-heater"
     dps:
-      - id: 60 
+      - id: 60
         type: string
         name: value
         range:
@@ -155,3 +156,16 @@ secondary_entities:
           - dps_val: 0
             value: false
           - value: true
+  - entity: binary_sensor
+    name: Seated
+    class: occupancy
+    icon: "mdi:toilet"
+    category: diagnostic
+    dps:
+      - id: 46
+        type: boolean
+        name: sensor
+        optional: true
+        mapping:
+          - dps_val: null
+            value: false