EMS water heater: update model details

Based on website, more detailed product name

custom_components/tuya_local/devices/ems_waterheater.yaml

@@ -2,7 +2,7 @@ name: Water heater
 products:
   - id: nqlqesmkrje7vdhm
     manufacturer: EMS
-    model: Thermal heat pump
+    model: 200L Magneto Thermo Tank
     model_id: TH200DT
 entities:
   - entity: water_heater