Function policy_scan_for_networks 

pub async fn policy_scan_for_networks<'a>(
    client_controller: ClientControllerProxy,
) -> Vec<ScanResult>

Returns a map with the scan results returned by the policy layer. The map is keyed by the id field of each fidl_fuchsia_policy::ScanResult.

This function will panic if the id field is ever None or if policy returns the same id twice. Both of these are invariants we expect the policy layer to uphold.