default CMIP7 CO2 files doesn't appear to be working?

### Brief summary of bug

WIEMIP simulations revealed that the original WIEMIP co2 file and the CMIP7 co2 file fail after 6 months in runs from 1850 to 2000:
https://github.com/ESCOMP/CTSM/issues/3936
For the WIEMIP simulations we seem to have solved the problem with a new file as posted here:
https://github.com/ESCOMP/CTSM/issues/3936#issuecomment-4595371239

### General bug information
Default CMIP7 file that fails:
`/glade/campaign/collections/gdex/data/d651077/cesmdata/inputdata/atm/datm7/CO2/co2_input4MIPs_GHGConcentrations_CMIP_CR-CMIP-1-0-0_gm_1750-2022_CMIP7_c20250228.nc`

Default CMIP6 files still works:
`/glade/campaign/cesm/cesmdata/inputdata/atm/datm7/CO2/fco2_datm_global_simyr_1750-2014_CMIP6_c180929.nc`

Sample directory (kind of hacky for WIEMIP), this is a CLM6 HIST case
`/glade/work/wwieder/wiemip/clm6_hh_ukesm_cou`

playing around with setting in user_nl_datm_stream for `co2tseries.cmip6_20tr`