fix(fisher_summer_air_conditioner): use diagnostic for sensor

From log in discussion #3483

custom_components/tuya_local/devices/fisher_summer_air_conditioner.yaml

@@ -647,7 +647,7 @@ entities:
     name: Fresh air filter
     class: problem
     hidden: unavailable
-    category: config
+    category: diagnostic
     dps:
       - id: 110
         type: bitfield