WRF-CTSM: Bottom layer specific humidty sent from the atmosphere model is less than zero

### Brief summary of bug

Iris Mužić (@irismuz) has reported the following error for her WRF-CTSM simulation after 11 days:

```
ERROR: Bottom layer specific humidty sent from the atmosphere model is less than zero.
```
This error is produced from `lnd_import_export_utils.F90` , where it checks specific humidity `forc_q_not_downscaled_grc` coming from the atmosphere with zero:
https://github.com/ESCOMP/CTSM/blob/d301320ce67516143aada70b9c1421d0dbe096d7/src/cpl/utils/lnd_import_export_utils.F90#L129-L134

She has checked the 2m specific humidity (Q2M) variable output from all produced ctsm_lilac.clm*.nc files, however, none of the time steps exhibit values less than zero.

### General bug information

**CTSM version you are using:** @irismuz can you please fill this