Fix FavoritesViewModel implementation

[JoaquimLey]

Due to the introduction of the Domain layer, the current implementation makes no sense (directly leaking SmsController)

• [x] Remove all of the SmsController related code

• [x] Handle (and execute) UseCases

• [x] Fix Unit tests

[JoaquimLey]

Closing as handling the remaining use-cases will make more sense when there's a decision (will open a new issue).