Save triangle material IDs and uvs during TriangleMesh::SelectByIndex.

[hanseuljun]

Type

• Bug fix (non-breaking change which fixes an issue): Fixes #
• New feature (non-breaking change which adds functionality). Resolves #
• Breaking change (fix or feature that would cause existing functionality to not work as expected) Resolves #

Motivation and Context

TriangleMesh::SelectByIndex was not copying material IDs and uv information to its output. This lack of information causes an issue when trying to render the output mesh.

Checklist:

• I have run python util/check_style.py --apply to apply Open3D code style
  to my code.
• This PR changes Open3D behavior or adds new functionality.
  • Both C++ (Doxygen) and Python (Sphinx / Google style) documentation is
    updated accordingly.
  • I have added or updated C++ and / or Python unit tests OR included test
    results (e.g. screenshots or numbers) here.
• I will follow up and update the code if CI fails.
• For fork PRs, I have selected Allow edits from maintainers.

Description

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This change is 

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

[ssheorey]

Thanks @hanseuljun for these updates!

[ssheorey]

Hi @hanseuljun please fix the code style so that we can merge this PR:

[] I have run python util/check_style.py --apply to apply Open3D code style
to my code.

You can also use make apply-style.

[ssheorey]

Hi @hanseuljun can you take a look and update this PR? Else, you can select Allow edits from maintainers.

[hanseuljun]

Sorry for a late reply...
Would it be possible to just pass this without the style check? PR is small and I've tried to keep the style exact. I remember the style check had version conflicts, which I thought would take long to fix so I've skipped. Instead I've tried hard to do style checking with my eyes.

And "allow edits from maintainers" does not work for repos from other orgs...
https://github.com/orgs/community/discussions/5634

[ssheorey]

Thanks @hanseuljun. Will fix style in next maintenance PR.

[hanseuljun]

Thanks for the understanding!