Remove unnecessary durability check in "ItemStack#isSimilar(...)"

By removing this check we avoid unnecessarily allocating useless `ItemMeta` objects if we are comparing two items, or one of the two items, that don't have any durability. Don't worry, the durability of the item is checked when it checks if both item metas are equal.

This is a leftover from when checking for the item's durability was "free" because the durability was stored in the `ItemStack` itself, this [was changed in Minecraft 1.13](f8b2086d60 (src)/main/java/org/bukkit/inventory/ItemStack.java).

paper-api/src/main/java/org/bukkit/inventory/ItemStack.java

@@ -307,7 +307,7 @@ public class ItemStack implements Cloneable, ConfigurationSerializable, Translat
             return true;
         }
         Material comparisonType = (this.type.isLegacy()) ? Bukkit.getUnsafe().fromLegacy(this.getData(), true) : this.type; // This may be called from legacy item stacks, try to get the right material
-        return comparisonType == stack.getType() && getDurability() == stack.getDurability() && hasItemMeta() == stack.hasItemMeta() && (hasItemMeta() ? Bukkit.getItemFactory().equals(getItemMeta(), stack.getItemMeta()) : true);
+        return comparisonType == stack.getType() && /* getDurability() == stack.getDurability() && */hasItemMeta() == stack.hasItemMeta() && (hasItemMeta() ? Bukkit.getItemFactory().equals(getItemMeta(), stack.getItemMeta()) : true); // Paper - remove redundant item durability check
     }
 
     @NotNull