CVE-2026-11811 Socket file-descriptor leak in UpdateHub OTA client start_coap_client() leading to resource-exhaustion DoS

The UpdateHub over-the-air update client's startcoapclient in subsys/mgmt/updatehub/updatehub.c leaks the CoAP/DTLS socket descriptor on its connection-setup failure paths. The shared error: cleanup gated socket closing on a ret 0 flag, but ret was set to -1 immediately after the socket was...