Core/Units: Implemented UNIT_VIS_FLAGS_INVISIBLE

Port From (https://github.com/TrinityCore/TrinityCore/commit/9653f96f9930c1c27bfec887bdbdc1a81b10babd)

Source/Framework/Constants/UnitConst.cs

@@ -270,8 +270,8 @@ namespace Framework.Constants
 
     public enum UnitVisFlags
     {
-        Unk1 = 0x01,
-        Creep = 0x02,
+        Invisible = 0x01,
+        Stealthed = 0x02,
         Untrackable = 0x04,
         Unk4 = 0x08,
         Unk5 = 0x10,

Source/Game/Spells/Auras/AuraEffect.cs

@@ -968,6 +968,8 @@ namespace Game.Spells
 
                 target.m_invisibility.AddFlag(type);
                 target.m_invisibility.AddValue(type, GetAmount());
+
+                target.SetVisFlag(UnitVisFlags.Invisible);
             }
             else
             {
@@ -1000,6 +1002,8 @@ namespace Game.Spells
                             playerTarget.RemoveAuraVision(PlayerFieldByte2Flags.InvisibilityGlow);
 
                         target.m_invisibility.DelFlag(type);
+
+                        target.RemoveVisFlag(UnitVisFlags.Invisible);
                     }
                 }
 
@@ -1057,7 +1061,7 @@ namespace Game.Spells
             {
                 target.m_stealth.AddFlag(type);
                 target.m_stealth.AddValue(type, GetAmount());
-                target.SetVisFlag(UnitVisFlags.Creep);
+                target.SetVisFlag(UnitVisFlags.Stealthed);
                 Player playerTarget = target.ToPlayer();
                 if (playerTarget != null)
                     playerTarget.AddAuraVision(PlayerFieldByte2Flags.Stealth);
@@ -1070,7 +1074,7 @@ namespace Game.Spells
                 {
                     target.m_stealth.DelFlag(type);
 
-                    target.RemoveVisFlag(UnitVisFlags.Creep);
+                    target.RemoveVisFlag(UnitVisFlags.Stealthed);
                     Player playerTarget = target.ToPlayer();
                     if (playerTarget != null)
                         playerTarget.RemoveAuraVision(PlayerFieldByte2Flags.Stealth);