Core/Unit: Fix DualWield Off-hand hit penalty (TrinityCore#30444)

* Offhand attacks that occur while on-next-hit abilities such as Heroic Strike are queued do not suffer the dual wield to-hit penalty.

src/server/game/Entities/Unit/Unit.cpp

@@ -12128,8 +12128,8 @@ float Unit::MeleeSpellMissChance(Unit const* victim, WeaponAttackType attType, i
     //calculate miss chance
     float missChance = victim->GetUnitMissChance();
 
-    // melee attacks while dual wielding have +19% chance to miss
-    if (!spellId && haveOffhandWeapon())
+    // Check if dual wielding, add additional miss penalty - when mainhand has on next swing spell, offhand doesnt suffer penalty
+    if (!spellId && haveOffhandWeapon() && attType != RANGED_ATTACK && !m_currentSpells[CURRENT_MELEE_SPELL])
         missChance += 19.0f;
 
     // bonus from skills is 0.04%