Core/Auras: Implemented SPELL_AURA_ADD_PCT_MODIFIER_BY_SPELL_LABEL and SPELL_AURA_ADD_FLAT_MODIFIER_BY_SPELL_LABEL

Port From (https://github.com/TrinityCore/TrinityCore/commit/ba4fa060d765a35507f1a73287504c3f2e440fdb)

Source/Framework/Constants/Spells/SpellAuraConst.cs

@@ -239,8 +239,8 @@ namespace Framework.Constants
         ArenaPreparation = 215,
         HasteSpells = 216,
         ModMeleeHaste2 = 217,
-        AddPctModifierBySpellLabel = 218, //NYI
-        AddFlatModifierBySpellLabel = 219, //NYI
+        AddPctModifierBySpellLabel = 218,
+        AddFlatModifierBySpellLabel = 219,
         ModAbilitySchoolMask = 220, //NYI
         ModDetaunt = 221,
         RemoveTransmogCost = 222,

Source/Framework/Constants/Spells/SpellConst.cs

@@ -400,6 +400,8 @@ namespace Framework.Constants
     {
         Flat = 0,                            // SPELL_AURA_ADD_FLAT_MODIFIER
         Pct = 1,                             // SPELL_AURA_ADD_PCT_MODIFIER
+        LabelFlat = 2,                            // SPELL_AURA_ADD_FLAT_MODIFIER_BY_SPELL_LABEL
+        LabelPct = 3,                            // SPELL_AURA_ADD_PCT_MODIFIER_BY_SPELL_LABEL
         End
     }