Distinguish between when the user declined the "Sign In" prompt or cancelled the flow in iOS

The issue https://github.com/FormidableLabs/react-native-app-auth/issues/565 suggests a way to differentiate between cancels from login failures.

But in iOS there are two types of cancellations in general:
1. when the user presses "Cancel" on the prompt, that is by declining to sign in itself which is before the browser flow is even started
2. when the user actually cancels the login flow or closes the browser

Is there anyway to distinguish between these two cases for iOS? For proper tracking purposes, I'd like to know when the user declines the prompt specifically.

Currently if you check the `error` as per suggested in [here](https://github.com/FormidableLabs/react-native-app-auth/issues/565#issuecomment-1036596709), both of these cases resolve to user cancellation which is based on this [-3 error code](https://github.com/openid/AppAuth-iOS/blob/e191b1beadf3041259652e6e464eaceff16e5fbb/Source/AppAuthCore/OIDError.h#L103).

Inizia esaminando la discussione sull'annullamento nell'issue 565 e il codice di errore referenziato di AppAuth-iOS Source/AppAuthCore/OIDError.h. Determina se i due percorsi di annullamento di iOS espongono segnali distinti tramite il bridge React Native; il lavoro è completato quando i chiamanti possono distinguere in modo affidabile il rifiuto della richiesta Sign In dall'annullamento o dalla chiusura del flusso del browser.

Scritto dal modello di indicizzazione a partire dal testo della issue.