For non-Adafruit bundles, the zip files produced during pull request CI do not contain the library's py or mpy files, because there is no way to provide an alternate package-prefix; this is currently only accepted when building releases.

This PR addresses the limitation by adding the new parameter. However, in order to build correctly, the individual libs still need to use it, similar to:

    - name: Run Build CI workflow
      uses: adafruit/workflows-circuitpython-libs/build@build-bundles-community-ci
      with:
        package-prefix: jepler_udecimal

(though after this PR is merged the workflow branch name would go back to @main)