fix(BT_ON_OFF): avoid false SKIP by polling bluetoothctl controller visibility

BT_ON_OFF was skipping when bluetoothctl did not immediately show the controller.
Poll for controller visibility after public-addr and keep output sanitization to
handle CR/ANSI noise in piped output. Also drop leading-underscore temp vars.

Signed-off-by: Srikanth Muppandam <smuppand@qti.qualcomm.com>

Author: smuppand