Fix res_grid_deg bug to allow either floats or a dict

[lewisblake]

Change Summary

Update res_grid_deg in colocation_setup.py to be either a float, dict, or None

Related issue number

Close #1226

Checklist

• Start with a draft-PR
• The PR title is a good summary of the changes
• PR is set to AeroTools and a tentative milestone
• Documentation reflects the changes where applicable
• Tests for the changes exist where applicable
• Tests pass locally
• Tests pass on CI
• At least 1 reviewer is selected
• Make PR ready to review

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.30%. Comparing base (e992544) to head (2a575be).
Report is 466 commits behind head on main-dev.

Additional details and impacted files

@@             Coverage Diff              @@
##           main-dev    #1227      +/-   ##
============================================
- Coverage     79.31%   79.30%   -0.01%     
============================================
  Files           131      131              
  Lines         20234    20246      +12     
============================================
+ Hits          16048    16057       +9     
- Misses         4186     4189       +3     

Flag	Coverage Δ
unittests	79.30% <100.00%> (-0.01%)	⬇️

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[thorbjoernl]

dict[Literal["lat_res_deg", "lon_res_deg"], float] | None -> `dict[Literal["lat_res_deg", "lon_res_deg"], float] | float | None nvm

If we use this other places in the code, consider using a typeddict: https://typing.readthedocs.io/en/latest/spec/typeddict.html#typeddict

[thorbjoernl]

LGTM