fix(NODE-6407): use conversationId returned by the server instead of hardcoded integer in SASL implementation for MONGODB-AWS. (#4258)

Author: kggau

src/cmap/auth/mongodb_aws.ts

@@ -148,7 +148,7 @@ export class MongoDBAWS extends AuthProvider {
 
     const saslContinue = {
       saslContinue: 1,
-      conversationId: 1,
+      conversationId: saslStartResponse.conversationId,
       payload: BSON.serialize(payload, bsonOptions)
     };