make translation audio depend on main audio connection / echo test

current state

when leaving the audio connection via , the connection to the translation audio stays active or is in undefined state

also it is possible to join as "listen only" and have translation audio active

goal

• the translation audio should only be available when the main audio is successfully connected (not via "listen only")
  • translation audio buttons should only be shown when there is an active main audio connection
• the user should leave both, the main audio and the translation audio when clicking on
• upon reconnecting to audio, both connections should be established using the device settings from echo-test
• in case there are errors, when connecting to main audio, do not make translation audio available