fix: NetworkConfig cached hash was not being regenerated on clients for each unique ConnectionRequestMessage [MTT-4605] (Unity-Technologies#2226)

MTT-4605
* fix
This resolves the issue where clients would not regenerate their NetworkConfig's hash value if a client disconnected from one server and tried to join another server.

* test
This validates that passing false to the NetworkConfig.GetConfig method generates a unique hash value.

* update
updating the changelog entry with the PR number.

Author: NoelStephensUnity

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -21,6 +21,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Fixed issue where clients were not rebuilding the `NetworkConfig` hash value for each unique connection request. (#2226)
 - Fixed the issue where player objects were not taking the `DontDestroyWithOwner` property into consideration when a client disconnected. (#2225)
 - Fixed issue #1924 where `UnityTransport` would fail to restart after a first failure (even if what caused the initial failure was addressed). (#2220)
 - Fixed issue where `NetworkTransform.SetStateServerRpc` and `NetworkTransform.SetStateClientRpc` were not honoring local vs world space settings when applying the position and rotation. (#2203)

com.unity.netcode.gameobjects/Runtime/Core/NetworkManager.cs

@@ -1616,7 +1616,9 @@ private void SendConnectionRequest()
         {
             var message = new ConnectionRequestMessage
             {
-                ConfigHash = NetworkConfig.GetConfig(),
+                // Since only a remote client will send a connection request,
+                // we should always force the rebuilding of the NetworkConfig hash value
+                ConfigHash = NetworkConfig.GetConfig(false),
                 ShouldSendConnectionData = NetworkConfig.ConnectionApproval,
                 ConnectionData = NetworkConfig.ConnectionData
             };

com.unity.netcode.gameobjects/Tests/Runtime/ConnectionApproval.cs

@@ -62,11 +62,27 @@ private void NetworkManagerObject_ConnectionApprovalCallback(NetworkManager.Conn
             response.PlayerPrefabHash = null;
         }
 
+
+        [Test]
+        public void VerifyUniqueNetworkConfigPerRequest()
+        {
+            var networkConfig = new NetworkConfig();
+            networkConfig.EnableSceneManagement = true;
+            networkConfig.TickRate = 30;
+            var currentHash = networkConfig.GetConfig();
+            networkConfig.EnableSceneManagement = false;
+            networkConfig.TickRate = 60;
+            var newHash = networkConfig.GetConfig(false);
+
+            Assert.True(currentHash != newHash, $"Hashed {nameof(NetworkConfig)} values {currentHash} and {newHash} should not be the same!");
+        }
+
         [TearDown]
         public void TearDown()
         {
             // Stop, shutdown, and destroy
             NetworkManagerHelper.ShutdownNetworkManager();
         }
+
     }
 }