ping_pong rand() is not seeded so device ids are likely the same across nodes

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## Issue template

- Hardware description: docker only
- RTOS: N/A
- Installation type: a containerized version of https://micro.ros.org/docs/tutorials/core/first_application_linux/
- Version or commit hash: b86db303dd7aed7ed34de2e1c2f94300c2ba7e4e
+ this patch to fix the stack corruption https://github.com/micro-ROS/micro-ROS-demos/pull/96

#### Steps to reproduce the issue
Build this repo on your target
```
cd /ros2_ws
. /opt/ros/humble/setup.bash
. install/local_setup.bash
colcon build --packages-select micro_ros_demos_rclc
/ros2_ws/install/micro_ros_demos_rclc/lib/micro_ros_demos_rclc/ping_pong
```

#### Expected behavior
I expect to see ping/pong messages

#### Actual behavior

You will see only Ping or only Pong messages

#### Additional information
Running on Ubuntu 24.04 host, docker compose driving a pair of containers to pubsub.

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In my testing, seeding random with a nanosecond clock is sufficient to generate different device ids. I'd file a PR but I'd like to see if this was intended or maybe just an artifact of launching two container simultaneously

Inizia dall’eseguibile ping_pong nel pacchetto micro_ros_demos_rclc e segui come vengono inizializzati i suoi ID dei dispositivi e lo stato di rand(). Riproduci il problema usando i comandi forniti per la build con colcon e per i container, quindi verifica che i due container si scambino messaggi sia Ping sia Pong con ID distinti.

Scritto dal modello di indicizzazione a partire dal testo della issue.