net: openthread: Bump OpenThread commit to f9d757a1
net: openthread: Bump OpenThread commit to f9d757a1

This version has cli_console backend fixed, hence no longer crashes on
`ot ping` command.

Signed-off-by: Robert Lubos <9d28997c6894a2d0321a7bb399169af7ce99b64e@nordicsemi.no>

finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,nashif/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,explora26/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,galak/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,ldts/zephyr,galak/zephyr,finikorg/zephyr,ldts/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,finikorg/zephyr,explora26/zephyr,explora26/zephyr,galak/zephyr,ldts/zephyr,nashif/zephyr,explora26/zephyr