Startup crash in TCon integration when prismarine additions disabled

[aran-gilman]

Minecraft version: 1.12.2 MMDLib version: 1.0.0 rc2.36 Base Metals version: 2.5.0- c2.332

Disabling prismarine additions in BaseMetals.cfg leads to a NullPointerException in the TCon integration code. I'm guessing this was fixed by #436, but that landed 3 days after the last release available on Curseforge.

Crash Report: crash-2019-08-31_09.42.12-client.txt