Core/Misc: Reduce header dependencies - Step III

src/server/game/Maps/MapManager.cpp

@@ -34,6 +34,8 @@
 #include "WorldPacket.h"
 #include "Group.h"
 #include "Player.h"
+#include "WorldSession.h"
+#include "Opcodes.h"
 
 extern GridState* si_GridStates[];                          // debugging code, should be deleted some day