The micro_ros_agent does not relay topic messages

還沒有人認領這個 Issue。

**Describe the bug**

Hi, I tried this example [micro-ros_subscriber_twist](https://github.com/micro-ROS/micro_ros_arduino/blob/humble/examples/micro-ros_subscriber_twist/micro-ros_subscriber_twist.ino) using UDP on STM32F407 (Ethernet), but the micro_ros_agent only relays the message to MCU if

```
[Normal]
Step 1: Start the agent
Step 2: Start the program on MCU
Step 3: Publish the twist message (keep publishing)

Twist messages received.
```

If I exchange step 2 with step 3, I cannot receive the message on MCU:

```
[BUG]
Step 1: Start the agent
Step 2: Publish the twist message (keep publishing)
Step 3: Start the program on MCU

No Twist messages.
```

I'm wondering is this an expected behavior or a BUG?

Besides, the [micro-ros_publisher.ino](https://github.com/micro-ROS/micro_ros_arduino/blob/humble/examples/micro-ros_publisher/micro-ros_publisher.ino) example cannot receive the int32 message under both scenarios.

**To Reproduce**

Scenario 1 (BUG):
```
$ Step 1: Start the agent
$ docker run -it -p 9999:9999/udp --privileged microros/micro-ros-agent:galactic udp4 -p 9999 -v 6

$ Step 2: Publish the twist message
$ docker container -it sleepy_rubin /bin/bash
$ # Inside the container
$ ros2 run teleop_twist_keyboard teleop_twist_keyboard

$ Step 3: Start the program on MCU
$ micro_ros_sub twist

# No twist message on MCU
```

Scenario 1 (Normal):
```
$ Step 1: Start the agent
$ docker run -it -p 9999:9999/udp --privileged microros/micro-ros-agent:galactic udp4 -p 9999 -v 6

$ Step 2: Start the program on MCU
$ micro_ros_sub twist

$ Step 3: Publish the twist message
$ docker container -it sleepy_rubin /bin/bash
$ # Inside the container
$ ros2 run teleop_twist_keyboard teleop_twist_keyboard

# Normal twist message on MCU
```

使用 galactic micro-ROS Agent Docker 命令、teleop_twist_keyboard，以及 micro_ros_subscriber_twist.ino 和 micro_ros_publisher.ino 範例，重現兩種順序情境。先比較 MCU 程式在發佈前啟動與在發佈後啟動時 agent 的行為和 logs；當預期訊息在兩個已記錄的情境中都能可靠傳遞，或預期限制已清楚記錄時，即視為完成。

由索引模型根據 Issue 內容生成。