feat(palicy_ecpro4_chlorinegenerator): improve compatibility

- make salinity and salt dosage optional, as devices do not seem to report
  them consistently
- add product id

Issue #3451

custom_components/tuya_local/devices/palicy_ecpro4_chlorinegenerator.yaml

@@ -1,8 +1,8 @@
 name: Chlorine generator
-# products:
-#   - id: UNKNOWN
-#     manufacturer: Palicy
-#     model: EC Pro 4
+products:
+  - id: 4lzloikpfiinsmea
+    manufacturer: Palicy
+    model: EC Pro 4
 entities:
   - entity: sensor
     name: Output
@@ -83,6 +83,7 @@ entities:
     dps:
       - id: 108
         type: integer
+        optional: true
         name: sensor
         unit: g/L
         class: measurement
@@ -93,6 +94,7 @@ entities:
     dps:
       - id: 109
         type: integer
+        optional: true
         name: sensor
         unit: kg
         class: measurement