fix(DB/Spells): Skullflame Shield's Drain Life should scale with spell power. (#11352)

data/sql/updates/pending_db_world/rev_1649612333538339500.sql

@@ -0,0 +1,5 @@
+INSERT INTO `version_db_world` (`sql_rev`) VALUES ('1649612333538339500');
+
+DELETE FROM `spell_bonus_data` WHERE `entry`=18817;
+INSERT INTO `spell_bonus_data` VALUES
+(18817,1,0,0,0,'Skullflame Shield - Drain Life');