Update to Minecraft 1.21.5-pre1 and Kotlin 2.1.10

This time I decided not to wait for Minecraft 1.21.5 to be released and update Silk to the first pre-release. So I created this PR as a draft and when 1.21.5 is released I'll update the Minecraft version, check if it is broken (and most likely not), and undraft the PR. A little bit of notes, as usual: - I added a null check to data in SerializableChunkDataMixin because Minecraft was just crashing when entering the world without it. I actually don't know why it was working before - A few versions ago Mojang disallowed using commands that can send messages from the player in `run_command` click event, so I replaced `/me` command with `/tellraw`