android: fix network change handling on API levels < 24

[dmytroreutov]

Fixes : #12313

In case if VPN toggled on<->off wasConnected returns true and delegate.enterIdle() is skipped.

PS: Not using android.net.ConnectivityManager.NetworkCallback#onCapabilitiesChanged for API 24+ can also be an issue if capabilities change and user needs to receive updates.

[linux-foundation-easycla]

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• ✅ login: dmytroreutov / name: dmytroreutov (b03cbf8)

[emil10001]

Overall looks good, suggested a minor change.

A bit of explanation here from looking through the docs, the NetworkReceiver here is registered to filter on broadcasts of CONNECTIVITY_ACTION, which has the following documentation:

A change in network connectivity has occurred. A default connection has either been established or lost. The NetworkInfo for the affected network is sent as an extra; it should be consulted to see what kind of connectivity event occurred.

This means that whenever this method is triggered, we know that a change in network has occurred. The if check tells us that we have an active connection. The !wasConnected check isn't useful because we just need to know that there was a change and now we do have an active connection.