We currently use `dotenv-expand@5` in `@next/env`, which does not support default expansion. It was added in v6 (https://github.com/motdotla/dotenv-expand/pull/39).
Upgrading to the latest version of `dotenv-expand` and fixing an import, the added test passed.
Fixes#34718
## 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 `yarn lint`