feat: Show compile time error if overriding unused OnServerAddPlayer (#…

…682)

* remove obsolete OnServerAddPlayer

BREAKING CHANGE: Remove obsolete OnServerAddPlayer

Any person that overrides this method has a broken game.  These methods are never called anywhere.

The user gets a warning because they are overriding an obsolete method,  which might get ignored if they have lots of other warnings.   They would run their game and their game would not work at all.  No errors.

By removing these methods, users that override these methods will get a compile time error instead.  So they cannot ignore this error and they will fix it.

* Method is no longer available in NetworkLobbyManager

Assets/Mirror/Components/NetworkLobbyManager.cs

@@ -195,12 +195,6 @@ public override void OnServerDisconnect(NetworkConnection conn)
             OnLobbyServerDisconnect(conn);
         }
 
-        [System.Obsolete("Use OnServerAddPlayer(NetworkConnection conn, AddPlayerMessage extraMessage) instead")]
-        public override void OnServerAddPlayer(NetworkConnection conn)
-        {
-            OnServerAddPlayer(conn, null);
-        }
-
         public override void OnServerAddPlayer(NetworkConnection conn, AddPlayerMessage extraMessage)
         {
             if (SceneManager.GetActiveScene().name != LobbyScene) return;

Assets/Mirror/Runtime/NetworkManager.cs

@@ -662,18 +662,6 @@ public virtual void OnServerReady(NetworkConnection conn)
             NetworkServer.SetClientReady(conn);
         }
 
-        [Obsolete("Use OnServerAddPlayer(NetworkConnection conn, AddPlayerMessage extraMessage) instead")]
-        public virtual void OnServerAddPlayer(NetworkConnection conn, NetworkMessage extraMessage)
-        {
-            OnServerAddPlayer(conn, null);
-        }
-
-        [Obsolete("Use OnServerAddPlayer(NetworkConnection conn, AddPlayerMessage extraMessage) instead")]
-        public virtual void OnServerAddPlayer(NetworkConnection conn)
-        {
-            OnServerAddPlayer(conn, null);
-        }
-
         public virtual void OnServerAddPlayer(NetworkConnection conn, AddPlayerMessage extraMessage)
         {
             if (LogFilter.Debug) Debug.Log("NetworkManager.OnServerAddPlayer");