* Add ServiceValidationError
* Add translation support
* Extend translation support to HomeAssistantError
* Add translation support for ServiceNotFound exc
* Frontend translation & translation_key from caller
* Improve fallback message
* Set websocket_api as default translation_domain
* Add MQTT ServiceValidationError exception
* Follow up comments
* Revert removing gueard on translation_key
* Revert test changes to fix CI test
* Follow up comments
* Fix CI test
* Follow up
* Improve language
* Follow up comment