Bump socket.io-parser from 3.3.3 to 3.3.4 in /slides

Bumps [socket.io-parser](https://github.com/Automattic/socket.io-parser) from 3.3.3 to 3.3.4.
- [Release notes](https://github.com/Automattic/socket.io-parser/releases)
- [Changelog](https://github.com/socketio/socket.io-parser/blob/3.3.4/CHANGELOG.md)
- [Commits](socketio/socket.io-parser@3.3.3...3.3.4)

---
updated-dependencies:
- dependency-name: socket.io-parser
  dependency-type: indirect
...

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Author: dependabot[bot]