[FUI22] Support getAllNetworkStateSnapshot

Currently, ConnectivityService has getAllNetworkState but it is
not ideal to expose as system API since the plan is to get rid
of NetworkState. Thus, create a new one that returns
NetworkStateSnapshot to fulfill the needs.

Note the original getAllNetworkState cannot be deleted now since
it has @UnsupportedAppUsage annotation.

Test: atest FrameworksNetTests
Bug: 174123988
Change-Id: Icddd434552b0e9ecbc8299e7242ec88cf3145aca
diff --git a/framework/api/module-lib-current.txt b/framework/api/module-lib-current.txt
index a9fd6f2..d2ed73e 100644
--- a/framework/api/module-lib-current.txt
+++ b/framework/api/module-lib-current.txt
@@ -6,6 +6,7 @@
   }
 
   public class ConnectivityManager {
+    method @NonNull @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public java.util.List<android.net.NetworkStateSnapshot> getAllNetworkStateSnapshot();
     method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public void registerSystemDefaultNetworkCallback(@NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void requestBackgroundNetwork(@NonNull android.net.NetworkRequest, @Nullable android.os.Handler, @NonNull android.net.ConnectivityManager.NetworkCallback);
     method @RequiresPermission(anyOf={android.Manifest.permission.MANAGE_TEST_NETWORKS, android.Manifest.permission.NETWORK_STACK}) public void simulateDataStall(int, long, @NonNull android.net.Network, @NonNull android.os.PersistableBundle);