Check NETWORK_SETTINGS permission for getAllNetworkStateSnapshots

This is declared in the API surface, but the implementation
does not match.

Ignore-AOSP-First: Needs cherry-picks
Test: atest CtsNetTestCases:android.net.cts.ConnectivityManagerTest#testGetAllNetworkStateSnapshots
Bug: 188140631
Change-Id: I97aa69651461ebe5c323ec669372f9a61b84e6a6