Improvements to EARU K6RH3A-WiFi (#3958)

* Fix Hysteresis step

custom_components/tuya_local/devices/earu_k6h3aw_thermostat.yaml

@@ -291,6 +291,7 @@ entities:
           max: 50
         mapping:
           - scale: 10
+            step: 5
       - id: 75
         type: integer
         optional: true