fix: allow product_attributes_extraction.ipynb to run on Vertex colab enterprise

[tianli]

Vertex AI colab enterprise does not allow fetching of external URI in Part.from_uri(), only gcs path (gs://...) is allowed. Therefore adding a function to load external image from URL and create the prompt part using Part.from_data().

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[holtskinner]

Can you also resolve the new notebook linter errors?