Added team EnderChests migration and minor code optimizations

Do i need to migrate my team EnderChests?

only if you are currently on 1.21.4 or below, or you did update to 1.21.5+ and you are having errors in the console.

how to migrate: https://ultimateteams.gitbook.io/ultimateteams-docs/setup/team-enderchests-migration

if you have any issue, join the Discord server

1.21.4+ ONLY

to prevent any future issue with the team EnderChests, and to be able to use new features available only in the latest versions, i had to update to 1.21.4+. I noticed from bStats that 90% of the servers are already on those versions, so i don't think it'll be a problem.