feat(Core/WorldObjects): implement Heartbeat timers (#20872)

src/server/game/Entities/Unit/Unit.cpp

@@ -386,7 +386,7 @@ void Unit::Update(uint32 p_time)
     // WARNING! Order of execution here is important, do not change.
     // Spells must be processed with event system BEFORE they go to _UpdateSpells.
     // Or else we may have some SPELL_STATE_FINISHED spells stalled in pointers, that is bad.
-    m_Events.Update(p_time);
+    WorldObject::Update(p_time);
 
     if (!IsInWorld())
         return;
@@ -15760,7 +15760,6 @@ void Unit::CleanupBeforeRemoveFromMap(bool finalCleanup)
     if (finalCleanup)
         m_cleanupDone = true;
 
-    m_Events.KillAllEvents(false);                      // non-delatable (currently casted spells) will not deleted now but it will deleted at call in Map::RemoveAllObjectsInRemoveList
     CombatStop();
     ClearComboPoints();
     ClearComboPointHolders();