refactor(Core/World): Create WorldSessionMgr to split session logic out of World (#21400)

src/server/game/Entities/Player/Player.cpp

@@ -84,6 +84,7 @@
 #include "World.h"
 #include "WorldPacket.h"
 #include "WorldSession.h"
+#include "WorldSessionMgr.h"
 #include "WorldState.h"
 #include <cmath>
 
@@ -363,7 +364,7 @@ Player::Player(WorldSession* session): Unit(true), m_mover(this)
 
     m_ControlledByPlayer = true;
 
-    sWorld->IncreasePlayerCount();
+    sWorldSessionMgr->IncreasePlayerCount();
 
     m_ChampioningFaction = 0;
 
@@ -447,7 +448,7 @@ Player::~Player()
     delete m_reputationMgr;
     delete _cinematicMgr;
 
-    sWorld->DecreasePlayerCount();
+    sWorldSessionMgr->DecreasePlayerCount();
 
     if (!m_isInSharedVisionOf.empty())
     {