glint language server not working in newly generate addon

[ef4]

When you run the blueprint with --typescript and --pnpm, you don't end up with a working language server in vscode.

I'm aware of typed-ember/glint#524, but neither putting @glint/core at the root nor using the Glint: Library Path solved the issue.

And even if we ignore the rest of the monorepo and open the addon by itself, we get a non-working language server, for which I filed typed-ember/glint#638

glint itself runs OK from the command line, it's the interactive language server integration that's breaking.