[Newton] Adds new CI job that pulls latest Newton builds

[kellyguo11]

Description

Adds a new CI job that runs tests on the latest newton commit off of main. It reads the mujoco-warp and mujoco versions from newton's uv.lock file.

Type of change

• New feature (non-breaking change which adds functionality)

Checklist

• I have read and understood the contribution guidelines
• 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