Scripts/MoltenCore: Fix logic at Ragnaros' Magma Blast casts

(should only be cast while the main target is not in melee range)

src/server/scripts/EasternKingdoms/BlackrockMountain/MoltenCore/boss_ragnaros.cpp

@@ -225,7 +225,7 @@ class boss_ragnaros : public CreatureScript
                                 events.ScheduleEvent(EVENT_ELEMENTAL_FIRE, urand(10000, 14000));
                                 break;
                             case EVENT_MAGMA_BLAST:
-                                if (me->IsWithinMeleeRange(me->GetVictim()))
+                                if (!me->IsWithinMeleeRange(me->GetVictim()))
                                 {
                                     DoCastVictim(SPELL_MAGMA_BLAST);
                                     if (!_hasYelledMagmaBurst)