Statistics Sync fixes for review

[AlexSlurp]

Hey! It's my first time doing something like this but this plugin is very helpful for my server and I just wanted others to have an alternative to the currently broken husky sync statistics sync, I installed the compiled plugin on both my backend servers and gave it a database to connect to and it was able to sync statistics across servers (statistics was the only thing I had selected in the config).
Here's a list of changes:

1. Filtered blocks from item statistics in order to support 1.20+ (I was getting enum class exceptions for wall hanging signs)
2. Adjusted load player statistics for above changes and handling 1.20+
3. Reversed JoinListener logic so players who have finished loading are given the ok (This fixed the account generation bug I had where we were unable to do anything until I rejoined and was given the flag, but I understand if you hate this change)
4. Any time the plugin prints a message to the player if the lang slot is empty it wont print an annoying space in chat (I kept the error calls unchanged since those are needed)

And that's about it, please let me know what you think, I hope this isn't a pain just wanted to shoot my thoughts. (I now understand the pain of syncing statistics)