Grant shell permissions for restart WiFi subsystem to Shell to support CTS

New permission is needed to allow CTS to trigger the new WiFi subsystem
restart API.

Bug: 175084231
Bug: 178125790
Test: atest android.net.wifi.cts.WifiManagerTest#testRestartWifiSubsystem
Change-Id: I0eb0362e6421480c10ba64f923a9069d1258d4ca