Fix: sun and datetimes dataloader issue

[peterdudfield]

Pull Request

Description

Fixing datetime bug

move sun and datetime features to coordinates, for some reason, torch.dataloader didnt load that dimension when it wasnt connected to any data.

openclimatefix/PVNet#304

How Has This Been Tested?

• TDD, so added a test
• then fixed it, and test passed

Checklist:

• My code follows OCF's coding style guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked my code and corrected any misspellings

[Sukh-P]

Great work fixing this! Thank you

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.58%. Comparing base (930d9ed) to head (f2a0b50).
Report is 28 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #140      +/-   ##
==========================================
- Coverage   92.69%   92.58%   -0.12%     
==========================================
  Files          39       40       +1     
  Lines        1123     1146      +23     
==========================================
+ Hits         1041     1061      +20     
- Misses         82       85       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.