Core/Spells: Removed old combo point code leftovers

Port From (https://github.com/TrinityCore/TrinityCore/commit/197d4369c894e9b088f862c7189f4fe20b4836ca)

Source/Game/Entities/Player/Player.Combat.cs

@@ -518,8 +518,8 @@ namespace Game.Entities
             opponent.RemoveAurasWithInterruptFlags(SpellAuraInterruptFlags2.DuelEnd);
 
             // cleanup combo points
-            ClearComboPoints();
-            opponent.ClearComboPoints();
+            SetPower(PowerType.ComboPoints, 0);
+            opponent.SetPower(PowerType.ComboPoints, 0);
 
             //cleanups
             SetDuelArbiter(ObjectGuid.Empty);

Source/Game/Entities/Player/Player.cs

@@ -645,8 +645,8 @@ namespace Game.Entities
 
                 // drunken state is cleared on death
                 SetDrunkValue(0);
-                // lost combo points at any target (targeted combo points clear in Unit::setDeathState)
-                ClearComboPoints();
+
+                SetPower(PowerType.ComboPoints, 0);
 
                 ClearResurrectRequestData();
 
@@ -723,7 +723,7 @@ namespace Game.Entities
                 StopCastingCharm();
                 StopCastingBindSight();
                 UnsummonPetTemporaryIfAny();
-                ClearComboPoints();
+                SetPower(PowerType.ComboPoints, 0);
                 GetSession().DoLootReleaseAll();
                 m_lootRolls.Clear();
                 OutdoorPvPMgr.HandlePlayerLeaveZone(this, m_zoneUpdateId);