[USB] If the user exits changes the app, connection needs to be established again

[AlexDochioiu]

It seems to not be possible to change or enter a ledger app after establishing USB connection. Doing so leads to error every single time when sending requests to the ledger.

Solution a: Need to throw some explicit error that the connection needs to be re-established.
Solution b: Need to automatically re-establish the connection on this error (assuming we can reliably detect that the failure is caused by the user being in the wrong app or having changed the app after initial connection)