[Internal-only] Resolve npm warning about unknown project config from pnpm

Running an npm command like `npm version` shows:

```
npm warn Unknown project config "auto-install-peers". This will stop working in the next major version of npm.
```

This is set in the .npmrc files in this project for pnpm https://pnpm.io/settings#autoinstallpeers but we should switch to a format that doesn't cause warnings from npm (e.g. not an npmrc but a pnpm-specific config file).