Added Updated Fetch Model

[ASzot]

Motivation and Context

The v1 Fetch Suction robot gripper URDF model had the issue where some of the links would create strange ghost forces that were very large (>1 million Newtons in a single time step). This change adds the download to get the fixed Fetch model that no longer has this issue.

How Has This Been Tested

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes.
• All new and existing tests passed.

[aclegg3]

Lab tests are failing. Is there a lab incompatibility with asset naming in a config or something?