Normalise unique ID in Axis integration (#45203)

* Move adding unique id to config entry from setup_entry to migrate_entry

* Normalise unique ID

* MQTT subscribe should still use the serial number in the way the device itself expects

homeassistant/components/axis/device.py

@@ -74,8 +74,8 @@ class AxisNetworkDevice:
         return self.config_entry.data[CONF_NAME]
 
     @property
-    def serial(self):
-        """Return the serial number of this device."""
+    def unique_id(self):
+        """Return the unique ID (serial number) of this device."""
         return self.config_entry.unique_id
 
     # Options
@@ -102,17 +102,17 @@ class AxisNetworkDevice:
     @property
     def signal_reachable(self):
         """Device specific event to signal a change in connection status."""
-        return f"axis_reachable_{self.serial}"
+        return f"axis_reachable_{self.unique_id}"
 
     @property
     def signal_new_event(self):
         """Device specific event to signal new device event available."""
-        return f"axis_new_event_{self.serial}"
+        return f"axis_new_event_{self.unique_id}"
 
     @property
     def signal_new_address(self):
         """Device specific event to signal a change in device address."""
-        return f"axis_new_address_{self.serial}"
+        return f"axis_new_address_{self.unique_id}"
 
     # Callbacks
 
@@ -151,8 +151,8 @@ class AxisNetworkDevice:
         device_registry = await self.hass.helpers.device_registry.async_get_registry()
         device_registry.async_get_or_create(
             config_entry_id=self.config_entry.entry_id,
-            connections={(CONNECTION_NETWORK_MAC, self.serial)},
-            identifiers={(AXIS_DOMAIN, self.serial)},
+            connections={(CONNECTION_NETWORK_MAC, self.unique_id)},
+            identifiers={(AXIS_DOMAIN, self.unique_id)},
             manufacturer=ATTR_MANUFACTURER,
             model=f"{self.model} {self.product_type}",
             name=self.name,
@@ -169,7 +169,9 @@ class AxisNetworkDevice:
 
         if status.get("data", {}).get("status", {}).get("state") == "active":
             self.listeners.append(
-                await mqtt.async_subscribe(hass, f"{self.serial}/#", self.mqtt_message)
+                await mqtt.async_subscribe(
+                    hass, f"{self.api.vapix.serial_number}/#", self.mqtt_message
+                )
             )
 
     @callback