Bluetooth: Host: add missing bt_conn_unref
Bluetooth: Host: add missing bt_conn_unref

conn is being referenced in `bt_conn_lookup_addr_le()`.

Signed-off-by: Jonathan Rico <fa71e224653c2b3d230eecbd20dc417397790bdf@nordicsemi.no>

zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr