Add tomllib to directories copied for Python zip.

[acolwell]

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PR Description

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
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What does this pull request do?

This just adds the tomllib directory to the list used to create the python zipfile. It appears that get-pip now appears to need tomllib and the installer build started failing because it was missing. Adding the directory fixed the "ModuleNotFoundError: No module named 'tomllib'" failure in get-pip.

Have you tested your changes (if applicable)? If so, how?

Yes. I've verified the installer builds successfully again with this fix.

[devernay]

LGTM