Issue Description: Dynmap is unable to render worlds with things like custom biome generation, such as the end biome in an overworld. In my case, I was coding a plugin to make a world with random biomes every block

• Dynmap Version: 3.4 beta 5 (spigot)
• Server Version: purpur 1.19 build 1715
• Pastebin of Configuration.txt: https://pastebin.com/ghgutXhC
• Server Host (if applicable): local (test server, eventually will be hosted somewhere)
• Pastebin of crashlogs or other relevant logs: https://pastebin.com/E4xEweai
• Other Relevant Data/Screenshots: none
• Steps to Replicate: Use a plugin with a CustomBiomeProvider and generate another world using it. Upon loading, there will be

[x] I have looked at all other issues and this is not a duplicate
[x] I have been able to replicate this

Has the fixed version been released yet or is the commit in the next release?