AB#3455870 Adds Authentication Constants to be used for broker latency timestamp in response, Fixes AB#3455870 (#2831)

[AB#3455870](https://identitydivision.visualstudio.com/fac9d424-53d2-45c0-91b5-ef6ba7a6bf26/_workitems/edit/3455870)
Adding Authentication constants necessary to support passing AST request
latency timestamps from Broker to OneAuth.

---------

Co-authored-by: prsaminathan <[email protected]>

Author: Prvnkmr337

changelog.txt

@@ -5,6 +5,7 @@ vNext
 - [MINOR] Cache Active Broker In Memory (BrokerDiscoveryClient) (#2817)
 - [MINOR] Enable Broker Discovery by default in MSAL/Broker API (#2818)
 - [MINOR] Fix for SDL violation in device pop scenarios, Fixes AB#3284510 (#2744)
+- [MINOR] Adds Authentication Constants to be used for broker latency timestamp in response (#2831)
 
 Version 23.1.1
 -----------

common4j/src/main/com/microsoft/identity/common/java/AuthenticationConstants.java

@@ -568,6 +568,15 @@ public static final class Broker {
          * String of broker client ID.
          */
         public static final String BROKER_CLIENT_ID = "29d9ed98-a469-4536-ade2-f981bc1d605e";
+        /**
+         * Timestamp when the broker received the authentication request.
+         */
+        public static final String BROKER_REQUEST_RECEIVED_TIMESTAMP = "broker_request_received_timestamp";
+
+        /**
+         * Timestamp when the broker generated the authentication response.
+         */
+        public static final String BROKER_RESPONSE_GENERATION_TIMESTAMP = "broker_response_generation_timestamp";
 
     }