Replace more generic ValueError with specific FileNotFoundError for warp.sim.load_mesh

[steinraf]

Category

• [ ] New feature
• [ ] Bugfix
• [ ] Breaking change
• [ ] Refactoring
• [ ] Documentation
• [X] Other

Description

Changing the error type of the warp.sim.load_mesh function for files which don't exist makes it easier to differentiate between wrong paths and invalid meshes programmatically.

Example: Iterating over multiple directories to find a mesh with a given name.

Changelog

Changes raise ValueError(f"File not found: {filename}") to raise FileNotFoundError(f"File not found: {filename}")

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• [X] Have you read the Contributor Guidelines?
• [ ] Have you written any new necessary tests?
• [ ] Have you added or updated any necessary documentation?
• [ ] Have you added any files modified by compiling Warp and building the documentation to this PR (.e.g. stubs.py, functions.rst)?
• [X] Does your code pass ruff check and ruff format --check?

[shi-eric]

Thanks for opening this PR!