Documentation: update the minimal version of recommended NodeJS version

[dannywillems]

It is currently mentioned that the minimal NodeJS version is 18+, see https://o1-labs.github.io/mina-rust/docs/developers/getting-started#3-additional-development-tools.
NodeJS is only used for the frontend, see the directory frontend.

However, the frontend should be compatible with NodeJS 24, and it should be the version recommended and installed in the CI as part of the documentation testing, see https://github.com/o1-labs/mina-rust/blob/develop/website/docs/developers/scripts/setup/install-nodejs.sh.
The NodeJS version should also be used in the Dockerfile of the frontend, see https://github.com/o1-labs/mina-rust/blob/develop/frontend/Dockerfile.