[Code] DiscordManager Global to Singleton Cleanup (#4926)

* [Code] DiscordManager Global to Singleton Cleanup

* Update discord_manager.h

---------

Co-authored-by: Chris Miles <akkadius1@gmail.com>

queryserv/zoneserver.cpp

@@ -5,9 +5,6 @@
 #include "../common/events/player_event_logs.h"
 #include "../common/discord/discord_manager.h"
 
-extern DiscordManager discord_manager;
-
-
 ZoneServer::ZoneServer(
 	std::shared_ptr<EQ::Net::ServertalkServerConnection> in_connection,
 	EQ::Net::ConsoleServer *in_console
@@ -38,7 +35,7 @@ void ZoneServer::HandleMessage(uint16 opcode, const EQ::Net::Packet &p)
 
 			player_event_logs.AddToQueue(n.player_event_log);
 
-			discord_manager.QueuePlayerEventMessage(n);
+			DiscordManager::Instance()->QueuePlayerEventMessage(n);
 			break;
 		}
 		default: {