defense bug fix

src/engine/objects/AbstractCharacter.java

@@ -956,6 +956,10 @@ public abstract class AbstractCharacter extends AbstractWorldObject {
         if (armor.template.item_skill_used.isEmpty())
             return ib.item_defense_rating;
 
+        if(armor.template.item_skill_used.length() < 1){
+            return ib.item_defense_rating;
+        }
+
         CharacterSkill armorSkill = playerCharacter.skills.get(armor.template.item_skill_used);
         if (armorSkill == null) {
             Logger.error("Player " + playerCharacter.getObjectUUID()