Configures mesh collision strategy in convert_mesh.py

[zehao-wang]

Description

The collision approximation configuration changed in main branch, but the code in tools/convert_mesh.py does not sync.

Fixes #3557

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read and understood the contribution guidelines
• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[Mayankm96]

It would be good to raise an error if none of the types match (and also avoiding a dangling if-else). Also please run the pre-commit formatter.