Prevent NPE when removing enchantment with no ItemMeta (#6459)

patches/server/Handle-Item-Meta-Inconsistencies.patch

@@ -183,6 +183,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 -            }
 +        // Paper start - replace entire method
 +        final ItemMeta itemMeta = this.getItemMeta();
++        if (itemMeta == null) return 0;
 +        int level = itemMeta.getEnchantLevel(ench);
 +        if (level > 0) {
 +            itemMeta.removeEnchant(ench);