load robot_description from other namespace

[RLi43]

Description

Add namespace to the topic to read robot_description

Checklist

• Required by CI: Code is auto formatted using clang-format
• [ / ] Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• [ / ] Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[sea-bass]

Thanks! For consistency, would it make more sense to instead create temp_node with the parent node's namespace using this constructor?

https://docs.ros.org/en/humble/p/rclcpp/generated/classrclcpp_1_1Node.html#_CPPv4N6rclcpp4Node4NodeERKNSt6stringERKNSt6stringERK11NodeOptions