Add unique id to ADS platforms (#20511)

* Add friendly_name option

* Correct hound findings

* correct hound findings 2

* add unique id

* add unique id to all ads platforms

homeassistant/components/ads/sensor.py

@@ -55,6 +55,7 @@ class AdsSensor(Entity):
         """Initialize AdsSensor entity."""
         self._ads_hub = ads_hub
         self._name = name
+        self._unique_id = ads_var
         self._value = None
         self._unit_of_measurement = unit_of_measurement
         self.ads_var = ads_var
@@ -84,6 +85,11 @@ class AdsSensor(Entity):
         """Return the name of the entity."""
         return self._name
 
+    @property
+    def unique_id(self):
+        """Return an unique identifier for this entity."""
+        return self._unique_id
+
     @property
     def state(self):
         """Return the state of the device."""