fix: multi-part services names being mangled incorrectly

[Carter12s]

I believe this is an appropriate fix for #65 , but I'm not certain.

[CLAassistant]

All committers have signed the CLA.

[0x53A]

I can confirm that this works - with the change, I can subscribe to a ROS2 Jazzy instance with rmw_zenoh_cpp. The same issue happens with topic names, not just service names.

On the ROS side, we are publishing sensor_msgs/Imu to /imu/data.
Without the change, we wouldn't receive any data on the rust side. With the change, it works.

I dumped all zenoh keys:

@/db1b671e2ed38b958740c13a0832dd93/router/publisher/0/imu/data/sensor_msgs::msg::dds_::Imu_/RIHS01_7d9a00ff131080897a5ec7e26e315954b8eae3353c3f995c55faf71574000b5b

@/ded286d03cb4abba3d16bc12daaa28f5/peer/publisher/0/imu/data/sensor_msgs::msg::dds_::Imu_/RIHS01_7d9a00ff131080897a5ec7e26e315954b8eae3353c3f995c55faf71574000b5b

As you can see, the publishers are not encoding the slashes.