Disable caching when fetching Level 1 and Level 2 JSON files

``` swift
extension URLSession {
    static let noCacheSession: URLSession = {
        let config = URLSessionConfiguration.default
        config.requestCachePolicy = .reloadIgnoringLocalAndRemoteCacheData
        return URLSession (configuration: config)
    } ()
}
```

See Hacking with Swift > Swift Concurrency by Example (Nov 2024) > Section 1 > video 7 (computed properties)