[Request]: Return if the connection uses a VPN instead of returning VPN as a result

### Plugin

connectivity_plus

### Use case

When using the plugin to detect if the user is on mobile data, vs non metered networks currently there is no way to tell if a user is connected when using a VPN. Because only VPN is returned we can't know if it's actually connected to the internet, or if it's a metered connection.

### Proposal

I would propose a breaking change. Instead of returning an enum, return an object similar to this:

```dart
class ConnectivityResult {
final ConnectivityType type; // An enum with the current enum values except vpn
final bool vpnConnection;
}

```

This allows actually checking the connectivity type when using a VPN. Currently there is no way to do that, at least on Android. On iOS since the VPN information is not exposed the flag could be false.

Il payload non indica file né test. Inizia nel plugin connectivity_plus individuando l’API attuale dell’enum di connettività e le relative implementazioni Android e iOS, quindi esamina come vengono esposte le informazioni VPN su ciascuna piattaforma; il lavoro è completato quando l’API proposta distingue lo stato VPN dal tipo di connettività sottostante.

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