fix: set cfields_to_perturb in cam-common-code from model_mod namelist

[hkershaw-brown]

Description:

The fields to perturb from model_nml for cam-fv and cam-se was not getting communicated to cam-common-code, so pert_model_copies exits without perturbing and fields since cfields_to_perturb=""

DART/models/cam-common-code/cam_common_code_mod.f90

Line 1059 in c5600dc

if (cfields_to_perturb(i) == '') exit

Fixes issue

fixes #845

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Documentation changes needed?

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.

Tests

Please describe any tests you ran to verify your changes.
Ran cam-fv filter case perturbing from a single instance, no inflation, not assimilating obs, checked output was perturbed.
Before fix output == input with perturb.
Not run cam-se yet.

Checklist for merging

• Updated changelog entry
• Documentation updated
• Update conf.py

Checklist for release

• Merge into main
• Create release from the main branch with appropriate tag
• Delete feature-branch

Testing Datasets

• Dataset needed for testing available upon request
• Dataset download instructions included
• No dataset needed

[Copilot]

Copilot wasn't able to review any files in this pull request.

Files not reviewed (2)

• models/cam-fv/model_mod.f90: Language not supported
• models/cam-se/model_mod.f90: Language not supported

[kdraeder]

Sorry that I didn't notice that you requested my review.
This fix looks straightforward.