Fix collision size for shoulder_link in ur10e.xml, line 81.

[midiexiangxxx]

Description

Wrong collision size for shoulder_link leads to an erroneous collision detection with the ground, generating large contact forces and causing instability in the simulation environment.

Fixes:
#192

Checklist

Please check off each item ([x]) once complete, or mark it as [N/A] if it doesn't apply:

• [N/A] Added your name to CONTRIBUTORS.md (alphabetically by first name)
• [N/A] Updated CHANGELOG.md:
  • [N/A] Global changelog (if your change affects the overall repo)
  • [N/A] Model-specific changelog (if it affects a specific model only)
• Followed the XML formatting/style guidelines (if editing MJCF)
• Ran pytest test/ locally and ensured all tests pass
• Signed the Contributor License Agreement (CLA)

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