Bluetooth: shell: stop l2cap TX when channel is disconnected
Bluetooth: shell: stop l2cap TX when channel is disconnected

Without this, the shell locks up when disconnected in the middle of a send
routine.

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

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