Don't show inspect contents on objects without contents

[TheDiscordian]

Fixes #263.

[spnda]

I guess it would make sense to remove the ternary here as there's no need for it anyway, as far as I can tell.

[TheDiscordian]

I guess it would make sense to remove the ternary here as there's no need for it anyway, as far as I can tell.

It looks like the ternary is there to handle offsetting other items:

            if (PlayerInventoryClipboard.contains(player.getUniqueId().toString())) {
                setItemStack(
                    getSize() - 4 - rightItemOffset,
                    Material.KNOWLEDGE_BOOK,
                    TranslationKey.INVENTORIES__PASTE_CONFIGURATION
                );
            }
            setItemStack(
                getSize() - 3 - rightItemOffset,
                Material.PAPER,
                TranslationKey.INVENTORIES__COPY_CONFIGURATION
            );
        }

        if (!isNotProtected && state.menuPermissions.contains(BlockAccessMenuEvent.MenuPermission.INFO)) {
            setItemStack(
                getSize() - 2 - rightItemOffset,
                Material.OAK_SIGN,
                TranslationKey.INVENTORIES__BLOCK_INFO
            );

I can change it to a boolean, and remove the references to the offset in these lines if you think it won't have side effects. However this code looks good to me.