Remove the old message responders

Leaves only an answer to "Who is Jellyfin", removing older ones for
EmbyServer and MediaBrowser_v2.

Emby.Server.Implementations/Udp/UdpServer.cs

@@ -41,8 +41,6 @@ namespace Emby.Server.Implementations.Udp
             _socketFactory = socketFactory;
 
             AddMessageResponder("who is JellyfinServer?", true, RespondToV2Message);
-            AddMessageResponder("who is EmbyServer?", true, RespondToV2Message);
-            AddMessageResponder("who is MediaBrowserServer_v2?", false, RespondToV2Message);
         }
 
         private void AddMessageResponder(string message, bool isSubstring, Func<string, IpEndPointInfo, Encoding, CancellationToken, Task> responder)