Improve logging in handleDataMessage and contact sync

ts/textsecure/messageReceiverEvents.ts

@@ -77,7 +77,8 @@ export class ContactSyncEvent extends Event {
   constructor(
     public readonly contacts: ReadonlyArray<ModifiedContactDetails>,
     public readonly complete: boolean,
-    public readonly receivedAtCounter: number
+    public readonly receivedAtCounter: number,
+    public readonly sentAt: number
   ) {
     super('contactSync');
   }