Ensure local notebook nodes use local env

[kevin-bates]

This change mirrors that of #1047 but for notebooks. Also, the local environment should be copied so as to not be side-affected by updates.

Updated the tests to include a pip install and import of the installed module to ensure its completion. If there are other lighter and more obscure packages than pygithub, suggestions are welcome. The primary requirement is that it can't exist prior to CI.

Fixes #1058

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