Describe the bug
The advancement Innumerable Trophies, for collecting all of the mob heads, requires you to collect an illusioner head. Since illusioners do not spawn anywhere in vanilla Minecraft, and Spectrum provides no way to spawn one, it's impossible to meet this requirement legitimately.

Expected behavior
I would expect unobtainable heads to be removed from the list of requirements for Innumerable Trophies. This is already the case for the monstrosity head, so why not for the illusioner head too?

Minecraft version
1.20.1

Mod version
1.7.14

Screenshots