Fix AN4 dataset links

[artbataev]

What does this PR do ?

Fix AN4 dataset link in docs. Remove broken links to AN4 data (no longer available).

Collection: [Docs, Tutorials]

Changelog

• fix AN4 dataset link in documentation
• remove broken AN4 links from tutorials

Usage

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# Add a code snippet demonstrating how to use this 

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PR Type:

• New Feature
• Bugfix
• Documentation

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Additional Information

• Related to # (issue)

[GNroy]

LGTM