FIxed issue where the indices were not created correctly.

[AntoineRichard]

Description

This PR fixes an issue in articulation object from omni.isaac.lab. The functions write_root_com_pose_to_sim and write_root_link_to_sim both result in an error where a variable is called before being assigned. I checked and there is a test for this, but I'm not sure why they don't catch it...

The two functions have been changed to match the behaviors of write_root_link_pose_to_sim and write_root_com_velocity_to_sim.

Fixes #1659

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[AntoineRichard]

I'll update the test function for the articulation to catch this error. It's only checking when no indices are passed, and that's why it wasn't caught in the tests.

[jtigue-bdai]

I'll update the test function for the articulation to catch this error. It's only checking when no indices are passed, and that's why it wasn't caught in the tests.

Thanks for catching this.