Draft e2e-test for %load_node magic

[noklam]

Description

The e2e test was not working due to subtle difference between running notebook programatically and from UI. This draft PR was the original tests that I created.

Development notes

Developer Certificate of Origin

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Checklist

• Read the contributing guidelines
• Signed off each commit with a Developer Certificate of Origin (DCO)
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes
• Checked if this change will affect Kedro-Viz, and if so, communicated that with the Viz team