Adding permission for Ethernet Network Management

Adding MANAGE_ETHERNET_NETWORKS as a signature level permission
to allow an application to dynamically change ethernet network values.

Bug: 210485380
Test: atest EthernetServiceTests

cherry pick of aosp/1964543

Change-Id: Icf9c2accc86735cc981adc0d5a24802e0616ffaf

framework-t/src/android/net/EthernetManager.java

@@ -358,6 +358,7 @@ public class EthernetManager {
         return proxy;
     }
 
+    @RequiresPermission(android.Manifest.permission.MANAGE_ETHERNET_NETWORKS)
     private void updateConfiguration(
             @NonNull String iface,
             @NonNull InternalNetworkUpdateRequest request,
@@ -372,6 +373,7 @@ public class EthernetManager {
         }
     }
 
+    @RequiresPermission(android.Manifest.permission.MANAGE_ETHERNET_NETWORKS)
     private void connectNetwork(
             @NonNull String iface,
             @Nullable @CallbackExecutor Executor executor,
@@ -385,6 +387,7 @@ public class EthernetManager {
         }
     }
 
+    @RequiresPermission(android.Manifest.permission.MANAGE_ETHERNET_NETWORKS)
     private void disconnectNetwork(
             @NonNull String iface,
             @Nullable @CallbackExecutor Executor executor,