net: lwm2m: LwM2M RD client registration update failure fix
net: lwm2m: LwM2M RD client registration update failure fix

Client jump to full registration state if registration update fail.
Update keep already opened DTLS session.

Signed-off-by: Juha Heiskanen <da286ad296b3dcaa6fdad737a1ad7c3ff3e427db@nordicsemi.no>

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