Pass robot_description content directly to ros2_control.launch.py

[marip8]

Rather than having the ros2_control.launch.py file re-run xacro on an input file, we should just pass the content of robot_description directly as an argument. This should help make the launch process simpler since ROS2 control arguments typically need to be provided to xacro (e.g., use_fake_hardware). Rather than doing this in multiple places, we can invoke xacro once with the desired arguments in the top-level launch file and pass around the contents of robot_description to the other launch files that need it

scan_n_plan_workshop/snp_motion_execution/launch/ros2_control.launch.py

Line 10 in c1cde0f

{'name': 'robot_description_file', 'description': 'Path to the URDF/xacro file', 'default': ''},

[marip8]

@DavidSpielman can you make a PR for this?