Symmetric follow-up to 47a3479490 which fixed
the same leak in media-sink. media-source transport_start() registers
update_delay_event and dups the transport fd before ensuring SCO I/O; on
HFP failure the fail path only deinited codec_data, leaking the event
source and fd. Early allocation failures also returned without cleanup.
Mirror media-sink: destroy update_delay_event, close the dup'd fd, clear
the decode buffer, and route early errors through the same fail path.
9bfea81847