release-please failed: Cannot convert undefined or null to object (package-lock.json with lockfileVersion: 1)

Thanks for stopping by to let us know something could be better!

Please provide the following details.

#### Environment details

- OS: Ubuntu 22.04 LTS (GitHub Public Runner)
- Node.js version: 18.20
- npm version: 10
- `release-please` version: 4

#### Steps to reproduce

1. Create a `package-lock.json` using `lockFileVersion: 1` (see [this example](https://github.com/mdn/data/blob/b62c9ee5a1d4ec3b7fcde9dbdd949559e45d118f/package-lock.json))
2. Run `release-please`.

#### Expected

Error message:

```
Your `package-lock.json` uses lockFileVersion X, which is not supported by release-please.
```

#### Actual

```
Cannot convert undefined or null to object
```

See [this action run](https://github.com/mdn/data/actions/runs/8602814519/job/23573454480).

#### Context

https://github.com/googleapis/release-please/blob/08331fa555ed482f675fb3e9dd5b0a5296e200a3/src/updaters/node/package-lock-json.ts#L46