Add implementation of getInterfaceHash()

Exempt-From-Owner-Approval: cherry-pick from internal
Bug: 136065010
Test: m
Change-Id: I314f19aeca82cc8653eab71c9526ea7a208e6b50
Merged-In: I314f19aeca82cc8653eab71c9526ea7a208e6b50

services/core/java/com/android/server/ConnectivityService.java

@@ -2955,6 +2955,11 @@ public class ConnectivityService extends IConnectivityManager.Stub
         public int getInterfaceVersion() {
             return this.VERSION;
         }
+
+        @Override
+        public String getInterfaceHash() {
+            return this.HASH;
+        }
     }
 
     private boolean networkRequiresPrivateDnsValidation(NetworkAgentInfo nai) {