contactSync should depend on syncMessage.complete

ts/textsecure/MessageReceiver.ts

@@ -3070,6 +3070,7 @@ export default class MessageReceiver
 
     const contactSync = new ContactSyncEvent(
       Array.from(contactBuffer),
+      Boolean(contacts.complete),
       envelope.receivedAtCounter
     );
     await this.dispatchAndWait(contactSync);

ts/textsecure/messageReceiverEvents.ts

@@ -76,6 +76,7 @@ export class ErrorEvent extends Event {
 export class ContactSyncEvent extends Event {
   constructor(
     public readonly contacts: ReadonlyArray<ModifiedContactDetails>,
+    public readonly complete: boolean,
     public readonly receivedAtCounter: number
   ) {
     super('contactSync');