* Refactor handling of exposed entities for cloud Alexa
* Tweak WS API
* Validate assistant parameter
* Address some review comments
* Refactor handling of exposed entities for cloud Google
* Raise when attempting to expose an unknown entity
* Add tests
* Adjust cloud tests
* Allow getting expose new entities flag
* Test Alexa migration
* Test Google migration
* Add WS command cloud/google_assistant/entities/get
* Fix return value
* Update typing
* Address review comments
* Rename async_get_exposed_entities to async_get_assistant_settings
Erik Montnemery