Update notebook links

[boomermath]

Description

Updated the links in the notebook, made minor changes to create_onnx.py for better backwards compatibility when using subprocess.run

Note: I will re update the notebook links for the newer create_onnx.py to match the merged version in another PR after this one is merged

Meta

Merge checklist:

• Pull Request title is short, imperative summary of proposed changes
• The description documents the what and why
• If this PR changes behavior or adds a feature, user documentation is updated
• If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• If this PR touches configuration, this is backwards compatible with settings back to v2024.3.1
• If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• If this PR addresses a bug, a regression test for it is added