fix(ledvance_smart_plabl100x25b): make advanced control optional

Recently added dp should be marked optional (not hidden), as it is generally write-only.

Issue #6247

custom_components/tuya_local/devices/ledvance_smart_plabl100x25b.yaml

@@ -165,5 +165,5 @@ entities:
     dps:
       - id: 28
         type: string
-        hidden: true
+        optional: true
         name: value