Cannot extend type "<some-type>" because it is not defined

If i extend types in my client-only schema, I get the above errors.

After some investigation, I found out that this actually only happens when reading the schema from a localhost URL like:

```
service: {
name: ,
url: 'http://localhost:3000/graphql',
skipSSLValidation: true,
},
```

When looking at my server, it actually does not look like the local URL is being used at all?

┆Issue is synchronized with this [Jira Task](https://apollographql.atlassian.net/browse/NEBULA-1022) by [Unito](https://www.unito.io)

Reproduce the error with a client-only schema that extends an undefined type and a service URL at http://localhost:3000/graphql. First verify which schema URL the VS Code extension reads; done means local schema loading works and extended types no longer produce the reported error.

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