[companion] Emit error when radio init fails

[adrienthebo]

Problem

When the example companion app inits, it will print Please wait..., attempt radio init, and then silently halt on radio init failure. The absence of error logging means that users can't determine if they've flashed the wrong firmware or if the radio has gotten hung during initialization.

Solution

Print a failure message on radio init failure.

[ripplebiz]

Thanks for this, but we always target the 'dev' branch for PR's, plus the UI code in dev is currently quite different, with two different ui's in different folders ('ui-new', 'ui-orig').