[1.21] Fix duplicate registration error for empty loot table

[XFactHD]

This PR fixes the duplicate registration error for the empty loot table when a loot table is loaded as empty due to resource conditions, the LootTableLoadEvent is canceled or the table is set to LootTable.EMPTY in the event.

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

Last commit published: 204949d02ddb9c5ba53f1cc68b11b1556793cd43.

PR Publishing

The artifacts published by this PR:

• 📦 net.neoforged:neoforge:21.0.22-beta-pr-1151-fix_loottable_load
• 📦 net.neoforged:testframework:21.0.22-beta-pr-1151-fix_loottable_load

Repository Declaration

In order to use the artifacts published by the PR, add the following repository to your buildscript:

repositories {
    maven {
        name 'Maven for PR #1151' // https://github.com/neoforged/NeoForge/pull/1151
        url 'https://prmaven.neoforged.net/NeoForge/pr1151'
        content {
            includeModule('net.neoforged', 'neoforge')
            includeModule('net.neoforged', 'testframework')
        }
    }
}

MDK installation

In order to setup a MDK using the latest PR version, run the following commands in a terminal.
The script works on both *nix and Windows as long as you have the JDK bin folder on the path.
The script will clone the MDK in a folder named NeoForge-pr1151.
On Powershell you will need to remove the -L flag from the curl invocation.

mkdir NeoForge-pr1151
cd NeoForge-pr1151
curl -L https://prmaven.neoforged.net/NeoForge/pr1151/net/neoforged/neoforge/21.0.22-beta-pr-1151-fix_loottable_load/mdk-pr1151.zip -o mdk.zip
jar xf mdk.zip
rm mdk.zip || del mdk.zip

To test a production environment, you can download the installer from here.

[ChampionAsh5357]

This is fine, though I would prefer a comment mentioning that this will be mapped to an empty Optional in LootDataType in case this breaks from a vanilla change in the future.