tools: remove dependency vulnerability checker

This change removes the script used to check for new vulnerabilities
in Node.js' dependencies, since it has been moved to its own
repository.

Refs: https://github.com/nodejs/nodejs-dependency-vuln-assessments
PR-URL: #45675
Reviewed-By: Rafael Gonzaga <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Richard Lau <[email protected]>

Author: facutuesca