What i did / Steps to reproduce

1. Install bluemap
2. Use /setblock ~ ~ ~ end_gateway to put an end gateway somewhere. Best if you surround it with some other block to you can better see it on the map.
3. Open the map, let it render. You cannot see the end gateway

Expected result

I should see the end gateway like any other block

Actual result

The end gateway is just not there. You cannot see it at all

Context

BlueMap Version:
bukkit 3.14 (commit 16b1300)

Purpur 1.20, overworld, no mods/plugins that would break end gateways. Just essentials and some economy stuff.

Mc view:

Bluemap view:

Added to #145, and closing this in favor of that other issue :)