Scripts/Spells: Fix damage on primart target of mage talent Supernova

Port From (https://github.com/TrinityCore/TrinityCore/commit/19a627b23ee2fb00d48fdf24fbdcefeae775455e)

Source/Scripts/Spells/Mage.cs

@@ -1123,6 +1123,25 @@ namespace Scripts.Spells.Mage
         }
     }
 
+    [Script] // 157980 - Supernova
+    class spell_mage_supernova : SpellScript
+    {
+        void HandleDamage(uint effIndex)
+        {
+            if (GetExplTargetUnit() == GetHitUnit())
+            {
+                int damage = GetHitDamage();
+                MathFunctions.AddPct(ref damage, GetEffectInfo(0).CalcValue());
+                SetHitDamage(damage);
+            }
+        }
+
+        public override void Register()
+        {
+            OnEffectHitTarget.Add(new EffectHandler(HandleDamage, 1, SpellEffectName.SchoolDamage));
+        }
+    }
+    
     [Script] // 80353 - Time Warp
     class spell_mage_time_warp : SpellScript
     {

sql/updates/world/master/2022_07_03_01_world_mage_supernova.sql

@@ -0,0 +1,3 @@
+DELETE FROM `spell_script_names` WHERE `spell_id` = 157980;
+INSERT INTO `spell_script_names` (`spell_id`, `ScriptName`) VALUES
+(157980, 'spell_mage_supernova');