Default root fields in console are incorrect for `graphql-default` naming convention

### Version Information

Server Version: v2.8.0-beta.1

### Environment

OSS

### What is the expected behaviour?

Show default GraphQL root fields correctly.

### Keywords

HASURA_GRAPHQL_DEFAULT_NAMING_CONVENTION, Custom GraphQL Root Fields

### What is the current behaviour?

Setting `HASURA_GRAPHQL_DEFAULT_NAMING_CONVENTION` to `graphql-default` still shows default GraphQL Root Field names as snake case (`hasura-default`).

### How to reproduce the issue?

1. Start Hasura v2.8.0-beta.1 with env var `HASURA_GRAPHQL_DEFAULT_NAMING_CONVENTION=true`
2. Create a table e.g. `customers`.
3. Go to the newly created table and click **Modify** and click **edit** under **Custom GraphQL Root Fields*.

### Screenshots or Screencast


### Any possible solutions?

Expose the root fields, even if no custom root fields are set, to set the default root fields in the console.

### Can you identify the location in the source code where the problem exists?

No

### If the bug is confirmed, would you be willing to submit a PR?

Yes, with some help.