Fixes#40133
Fixes a small regression introduced in #39872. We should be able to detect if a non-empty `package.json#eslintConfig` property is present.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
We shouldn't be warning when no eslint config file is present as it's valid not to use eslint. The warning is still shown if an empty eslint config file is added as this gives intent to using eslint.
x-ref: [slack thread](https://vercel.slack.com/archives/CGU8HUTUH/p1661268593890619?thread_ts=1661266342.496699&cid=CGU8HUTUH)
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
