Fix posix shm loop

[cybaol]

To fix this:
E20251122 13:36:22.462062 429071 posix_segment.cc:269] [cyber_py]open only failed. [1] 429049 segmentation fault (core dumped) cyber_channel echo /tf_static

Enabling POSIX shared memory causes core dumps when subscribing to channels such as /tf_static.

[cybaol]

This is my config:

// cyber.pb.conf
transport_conf {
    shm_conf {
        # "multicast" "condition"
        notifier_type: "condition"
        # "posix" "xsi"
        shm_type: "posix"
        shm_locator {
            ip: "239.255.0.100"
            port: 8888
        }
    }
    participant_attr {
        lease_duration: 12
        announcement_period: 3
        domain_id_gain: 250
        port_base: 7400
    }
    communication_mode {
        same_proc: INTRA
        diff_proc: SHM
        diff_host: RTPS
    }
    resource_limit {
        max_history_depth: 1000
    }
}

run_mode_conf {
    run_mode: MODE_REALITY
    clock_mode: MODE_CYBER
}

scheduler_conf {
    routine_num: 50
    default_proc_num: 6
}