Ensure Copilot Coding Agent has access to vsce-downloaded VS Code for extension integration tests #123
Description
Update .github/workflows/copilot-setup-steps.yml, and possibly the extensions/vscode/package.json devDependencies, to ensure that Copilot Coding Agent has access to the vsce-downloaded instance of VS Code — which would be needed for Copilot Coding Agent to be able to actually run the test:integration tests for the extension.