AP_DDS: revert change that removed namespace for TF subscriber topic

[srmainwaring]

Without a namespace prefix the micro-ROS agent will attempt to send all /tf messages to ArduPilot DDS. This can quickly overwhelm the AP_DDS subscriber for large TF trees.

The preferred approach should be to use a topic_tools relay node to forward TF only when required, and prune the tree with a filter if appropriate.

Testing

Without this change the rover example

ros2 launch ardupilot_gz_bringup wildthumper_playpen.launch.py rviz:=true use_gz_tf:=true

results in continuous reporting of [RTPS_READER_HISTORY Error]

[micro_ros_agent-3] 2023-10-27 09:21:03.217 [RTPS_READER_HISTORY Error] Change payload size of '1764' bytes is larger than the history payload size of '1031' bytes and cannot be resized. -> Function can_change_be_added_nts
[micro_ros_agent-3] 2023-10-27 09:21:03.265 [RTPS_READER_HISTORY Error] Change payload size of '1764' bytes is larger than the history payload size of '1031' bytes and cannot be resized. -> Function can_change_be_added_nts
[micro_ros_agent-3] 2023-10-27 09:21:03.316 [RTPS_READER_HISTORY Error] Change payload size of '1764' bytes is larger than the history payload size of '1031' bytes and cannot be resized. -> Function can_change_be_added_nts

This is because the rover TF tree is large:

With the change the error is not reported.

[Ryanf55]

I support this change. Yes, as @pedro-fuoco had originally found, it's annoying to deal with the remappings everywhere, but this is a necessary evil when working on a resource-constrained environment like ArduPilot where MicroXRCEDDS can't chunk payloads.

[srmainwaring]

Also, we will need the prefix when we start dealing with more than one vehicle, and this keeps the topics consistent at least.