Update cloth example with new ModelBuilder coloring API

[astefanutti]

Category

• New feature
• Bugfix
• Breaking change
• Refactoring
• Documentation
• Other (please explain)

Description

This updates example_cloth.py according to the ModelBuilder API changes introduced in 5205ebb.

Changelog

• Add specific line-by-line info of high level changes in this PR.

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[shi-eric]

Thanks for your contribution!