Improved:
- Remove unused permissions READ_PHONE_STATE, READ_EXTERNAL_STORAGE, WRITE_EXTERNAL_STORAGE
- [Vosk] Do not start downloading the model right away, but show a download icon

Fixed:
- [Vosk] Heavily improve model downloading strategy, fixing many unexpected behaviors
- [Vosk] Now the download or loading icons are preserved when resuming the app, instead of wrongfully replacing them with the microphone off icon
