The feature_request path for Centurion sub-device features routes
through centurion_bridge_request, which returned None silently when
the sub-device replied with sub_feat_idx=0xFF (error marker). The
existing log was at DEBUG, invisible for users whose -dd doesn't
turn on DEBUG-level output.
The write-returned-no-reply INFO we added recently caught mic-gain /
sidetone / auto-sleep writes failing with no visible log about WHY.
Bumping this log to INFO surfaces the original feat_idx, function,
and error code so we can distinguish transport timeout vs device
rejection, and debug what exactly the G522 dislikes about our writes.
No behavior change — same return value (None), just more visible log.