DB: added a missing spell script name from a cherrypick

sql/updates/world/4.3.4/2022_05_07_00_world.sql

@@ -0,0 +1,4 @@
+DELETE FROM `spell_script_names` WHERE `ScriptName`='spell_gen_50pct_count_pct_from_max_hp' AND `spell_id`=48292;
+DELETE FROM `spell_script_names` WHERE `ScriptName`='spell_dark_slash';
+INSERT INTO `spell_script_names` (`spell_id`, `ScriptName`) VALUES
+(48292, 'spell_dark_slash');