Ensure unique_ids for all evohome thermostats (#32604)

* initial commit

* small tweak

homeassistant/components/evohome/climate.py

@@ -149,7 +149,12 @@ class EvoZone(EvoChild, EvoClimateDevice):
         """Initialize a Honeywell TCC Zone."""
         super().__init__(evo_broker, evo_device)
 
-        self._unique_id = evo_device.zoneId
+        if evo_device.modelType.startswith("VisionProWifi"):
+            # this system does not have a distinct ID for the zone
+            self._unique_id = f"{evo_device.zoneId}z"
+        else:
+            self._unique_id = evo_device.zoneId
+
         self._name = evo_device.name
         self._icon = "mdi:radiator"