Land use x PFT history variables currently don't work

[ckoven]

Describe the issue

There is some stub infrastructure for land use x PFT -dimensioned variables in FATES, but there aren't currently any variables on that dimension, and if one tries to add them they don't work. I have code that fixes this, which requires changes to both FATES and ELM.

The ELM commit allows this is: ckoven/E3SM@a8d447e

I've also made a FATES branch off of main that has two new variables (area and biomass) on the LU x PFT dimension. These variables are useful for understanding dynamics in nocomp runs with land use change: https://github.com/ckoven/fates/tree/lupft_dimension

Relevant log output

FATES tag

main

Host land model tag

ELM master

Machine

perlmutter

Other supported machine name

No response

Additional context

No response