Core/Spells&GOs: Fix Ritual of Doom.

Thanks QAston and Shocker for helping.
Closes #2535

src/server/game/Spells/SpellEffects.cpp

@@ -419,6 +419,7 @@ void Spell::SpellDamageSchoolDmg(SpellEffIndex effIndex)
                         damage = unitTarget->CountPctFromMaxHealth(50);
                         break;
                     }
+                    case 20625: // Ritual of Doom Sacrifice
                     case 29142: // Eyesore Blaster
                     case 35139: // Throw Boom's Doom
                     case 55269: // Deathly Stare