issue with build.sh and CI script

Hey, when fixing up my forked bundle to generate mpy files again (CI died after 2yrs of no changes), it had problems with the package names and didn't generate expected assets.

https://github.com/good-enough-technology/CircuitPython_GoodEnough_Bundle/pull/1

This PR was claude working through it with a mini fix until I asked about path based injection as the steps chain, classically it had made things worse...

Anyway, here's a single commit that avoids the chaining risk and fixes the issue.
There's probably a more elegant solution, but my Fable budget is low so this was opus😄

#290

-edit-
` package_folder_prefix is only consulted when a library has no [tool.setuptools] metadata in pyproject.toml. `

Start by reading build.sh and the CI script, then compare their package-name and asset-generation behavior with the referenced fork pull request and issue #290. Check the relevant pyproject.toml metadata, and consider the work complete when the bundle generates the expected mpy assets with correct package names in CI.

Written by the indexing model from the issue text.