Open API endpoint is missing when using the database generated API

**Describe the bug**

The database generate API uses [data-api-builder](https://github.com/Azure/data-api-builder) under the hood. This API generator normally provides under the path `/rest/openapi`, the openapi document, needed for many tools to connect to your API.

**To Reproduce**
Steps to reproduce the behavior:
1. Deploy a static webapp
2. Deploy a Azure SQL (use the adventure works sample for your database)
3. Go to your static webapp and configure a database connection
4. Deploy a valid `staticwebapp.database.config.json`
5. Try to navigate to `/rest/openapi`

You will get the following error:

```json
{
"error": {
"code": "EntityNotFound",
"message": "Invalid Entity path: openapi.",
"status": 404
}
}
```

this should work since https://github.com/Azure/data-api-builder/releases/tag/v0.7.6 of the data-api-builder