Automatically validate converter output with appropriate tooling

[andrewkaufman]

Is this a new feature, an improvement, or a change to existing functionality?

New Feature

Feature Description

Ensure the converter output passes asset validation for both UsdValidation framework & the Omni Asset Validator used in the current unittests.

Additional context or alternatives

Wait for the nested bodies validation to land before working on this

Code of Conduct

• I agree to follow mujoco-usd-converter Code of Conduct
• I have searched the open issues and have found no duplicates