fix: new message versioning starting after session owner message (#2942)

* fix

We are starting the message versioning after the more recent session owner message.

* update

adding change log entry

* update

adding PR number to changelog entry.

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -8,6 +8,10 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed issue where SessionOwner message was being treated as a new entry for the new message indexing when it should have been ordinally sorted with the legacy message indices. (#2942)
+
 ## [2.0.0-exp.4] - 2024-05-31
 
 ### Added

com.unity.netcode.gameobjects/Runtime/Messaging/ILPPMessageProvider.cs

@@ -44,9 +44,9 @@ namespace Unity.Netcode
             SceneEvent = 17,
             ServerLog = 18,
             ServerRpc = 19,
-            TimeSync = 20,
-            Unnamed = 21,
-            SessionOwner = 22
+            SessionOwner = 20,
+            TimeSync = 21,
+            Unnamed = 22,
         }