Fall back to polling if webhook cannot be registered on Nuki (#91013)

fix(nuki): throw warning if webhook cannot be created

homeassistant/components/nuki/helpers.py

@@ -13,3 +13,7 @@ class CannotConnect(exceptions.HomeAssistantError):
 
 class InvalidAuth(exceptions.HomeAssistantError):
     """Error to indicate there is invalid auth."""
+
+
+class NukiWebhookException(exceptions.HomeAssistantError):
+    """Error to indicate there was an issue with the webhook."""