Scripts: fix spell_generic_quest_update_entry script after e949ad3adb.

src/server/scripts/Spells/spell_quest.cpp

@@ -56,7 +56,7 @@ public:
 
     void Register()
     {
-        OnEffectHit += SpellEffectFn(spell_generic_quest_update_entry_SpellScript::HandleDummy, _effIndex, _spellEffect);
+        OnEffectHitTarget += SpellEffectFn(spell_generic_quest_update_entry_SpellScript::HandleDummy, _effIndex, _spellEffect);
     }
 };