Bump Node version to v22.21.1

[github-actions]

The Node version used in the latest version of VS Code has been updated. This PR updates the Node version used for integration tests to match.
The previous Node version was v22.20.0. This PR updates the Node version to v22.20.0.

[Copilot]

Pull request overview

This PR updates the Node.js version used for integration tests from v22.20.0 to v22.21.1 to match the Node version in the latest VS Code release. The update is applied consistently across all configuration files.

• Updated Node.js version constraint from ^22.20.0 to ^22.21.1
• Updated @types/node dependency from 22.19.1 to 22.19.2
• Updated .nvmrc to specify v22.21.1

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

File	Description
extensions/ql-vscode/package.json	Updates Node engine requirement from ^22.20.0 to ^22.21.1
extensions/ql-vscode/package-lock.json	Updates Node engine requirement and @types/node dependency version
extensions/ql-vscode/.nvmrc	Updates Node version from v22.20.0 to v22.21.1 for nvm

Files not reviewed (1)

• extensions/ql-vscode/package-lock.json: Language not supported

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[Copilot]

The PR description contains an error. It states "The previous Node version was v22.20.0. This PR updates the Node version to v22.20.0." Both versions mentioned are the same (v22.20.0), but based on the actual changes in the code, it should read "This PR updates the Node version from v22.20.0 to v22.21.1."