Function deltachat::scheduler::connectivity::maybe_network_lost

pub(crate) async fn maybe_network_lost(
    context: &Context,
    stores: Vec<ConnectivityStore>,
)

Set the connectivity to “Not connected” after a call to dc_maybe_network_lost(). If we did not do this, the connectivity would stay “Connected” for quite a long time after maybe_network_lost() was called.