[bug] Project info missing when `DBML->JSON->DBML`

I make a prettier-plugin for DBML: https://github.com/nice-move/prettier-plugin-dbml

But I find out that project info will be missing when converting DBML to * and * to DBML.

```js
const { exporter } = require('@dbml/core');

const string = `
Project project_name {
database_type: 'PostgreSQL'
Note: 'Description of the project'
}
`

exporter.export(string, 'dbml') // -> ''
```