Copy clat modified linkProperties into new one.

updateLinkProperties copied the linkProperties in networkAgent,
but the clat fix-up function did not copy stacked link into new one.
This caused an incorrect clat iface removal, and the IPv4 network
 to be unreachable.

Bug: 80261579
Test: 1. ping after ipv6 only data call with 2g voice call on/off
      2. runtest frameworks-net
      3. run cts -m CtsNetTestCases
Change-Id: Ide47a3b0680dddfcf3e2e759a59b19aee3605050

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

@@ -4690,7 +4690,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
         // The NetworkAgentInfo does not know whether clatd is running on its network or not. Before
         // we do anything else, make sure its LinkProperties are accurate.
         if (networkAgent.clatd != null) {
-            networkAgent.clatd.fixupLinkProperties(oldLp);
+            networkAgent.clatd.fixupLinkProperties(oldLp, newLp);
         }
 
         updateInterfaces(newLp, oldLp, netId, networkAgent.networkCapabilities);

services/core/java/com/android/server/connectivity/Nat464Xlat.java

@@ -224,15 +224,14 @@ public class Nat464Xlat extends BaseNetworkObserver {
     }
 
     /**
-     * Copies the stacked clat link in oldLp, if any, to the LinkProperties in mNetwork.
+     * Copies the stacked clat link in oldLp, if any, to the passed LinkProperties.
      * This is necessary because the LinkProperties in mNetwork come from the transport layer, which
      * has no idea that 464xlat is running on top of it.
      */
-    public void fixupLinkProperties(LinkProperties oldLp) {
+    public void fixupLinkProperties(LinkProperties oldLp, LinkProperties lp) {
         if (!isRunning()) {
             return;
         }
-        LinkProperties lp = mNetwork.linkProperties;
         if (lp == null || lp.getAllInterfaceNames().contains(mIface)) {
             return;
         }