Core/Spell: do positivity spell checks only against actually hitted effects instead of the whole spell

Closes #18097

src/server/game/Spells/Spell.cpp

@@ -2352,7 +2352,19 @@ void Spell::DoAllEffectOnTarget(TargetInfo* target)
         if (m_damage > 0)
             positive = false;
         else if (!m_healing)
-            positive = m_spellInfo->IsPositive();
+        {
+            for (uint8 i = 0; i < MAX_SPELL_EFFECTS; ++i)
+            {
+                if (!(target->effectMask & (1 << i)))
+                    continue;
+
+                if (!m_spellInfo->IsPositiveEffect(i))
+                {
+                    positive = false;
+                    break;
+                }
+            }
+        }
 
         switch (m_spellInfo->DmgClass)
         {