Add a file to the CMakeLists.txt needed for CTSM unit tests for the decomposition

[ekluzek]

Describe the changes

In ESCOMP/CTSM#3412 I add a unit tester for the CTSM decompInit that requires FATES files for dependencies. There's one additional file I need from FATES for this. This should be fine on the FATES side, and I'll try to run the unit-testing when I create the PR for this.

diff --git a/radiation/CMakeLists.txt b/radiation/CMakeLists.txt
index feda02d4..b10d81fa 100644
--- a/radiation/CMakeLists.txt
+++ b/radiation/CMakeLists.txt
@@ -1,6 +1,7 @@
 # This file is required for unit testing, but is not used for production runs
 list(APPEND fates_sources
   TwoStreamMLPEMod.F90
+  FatesTwoStreamUtilsMod.F90
   FatesRadiationMemMod.F90)
 
 sourcelist_to_parent(fates_sources)

Is your request related to a problem?

Allows the CTSM decompInit PF unit test to work.

Alternative options

No response

Additional context

No response