Mark NetworkAgentConfig fit for inclusion in stable AIDL

Test: m together with its topic
Change-Id: I897a2081fb48a614f28d9ec3965f99cca9f8ec62
diff --git a/framework/aidl-export/android/net/NetworkAgentConfig.aidl b/framework/aidl-export/android/net/NetworkAgentConfig.aidl
index cb70bdd..02d50b7 100644
--- a/framework/aidl-export/android/net/NetworkAgentConfig.aidl
+++ b/framework/aidl-export/android/net/NetworkAgentConfig.aidl
@@ -16,4 +16,4 @@
 
 package android.net;
 
-parcelable NetworkAgentConfig;
+@JavaOnlyStableParcelable parcelable NetworkAgentConfig;