Fix: Update link in about.tsx to new chapter location

[rafael-abuawad]

Fixes broken The EVM Chapter in the Mastering Ethereum book link

Old link: The EVM Chapter in the Mastering Ethereum book
New link: The EVM Chapter in the Mastering Ethereum book

[vercel]

@rafael-abuawad is attempting to deploy a commit to the Duneanalytics Team on Vercel.

A member of the Team first needs to authorize it.

[cursor]

PR Summary

Low Risk
Single external URL change in documentation copy with no runtime or security impact.

Overview
Updates the Mastering Ethereum resource link on the About page so it points at the book’s current chapter file instead of a removed AsciiDoc path.

The anchor text is unchanged; only the href moves from 13evm.asciidoc on develop to src/chapter_14.md on the same repo.

^{Reviewed by Cursor Bugbot for commit b4cb9f9. Configure here.}