Add clatd binary to apex

Ship clatd binary with apex. This makes that the clatd binary becomes
updatable.

Bug: 212345928
Test: manual test
1. Connect to ipv6-only wifi.
2. Make IPv4 traffic.
   $ ping 8.8.8.8

Change-Id: I4f6f0944e94e165983a19a5d3c3a117274f6bbac
diff --git a/Tethering/apex/Android.bp b/Tethering/apex/Android.bp
index ee1c5fe..4703f1d 100644
--- a/Tethering/apex/Android.bp
+++ b/Tethering/apex/Android.bp
@@ -58,6 +58,9 @@
             jni_libs: ["libframework-connectivity-jni"],
         },
     },
+    binaries: [
+        "clatd",
+    ],
     bpfs: [
         "offload.o",
         "test.o",