OpenAPI import fails on valid Logto schema

### Version Information

Server Version: v2.35.0

### Environment
OSS

### What is the current behaviour?
The import UI reports the following:
```
Invalid spec: Cannot use 'in' operator to search for '$ref' in undefined
```

Also see ticket https://github.com/logto-io/logto/issues/4864

### How to reproduce the issue?

1. Install Logto version 1.10.1
2. Copy the OpenAPI specification from `/api/swagger.json`
3. Paste into Hasura OpenAPI import.

### Screenshots or Screencast

### Please provide any traces or logs that could help here.
[swagger.json](https://github.com/hasura/graphql-engine/files/13326505/swagger.json)