Add test coverage for ERA5 wind data with height dimension (Issue #66)

[munniomer]

This PR adds test coverage to ensure that preprocessing works correctly for standard ERA5 wind data containing an additional height dimension.

The test verifies that the height dimension is preserved and remains unaffected by the preprocessing steps, while the existing spatial and temporal processing behaves as expected.

This aligns the preprocessing pipeline with standard ERA5 (non-LAND) NetCDF files where wind variables include a vertical dimension.

Closes #66.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.76%. Comparing base (3bfea3c) to head (544f9b9).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #102   +/-   ##
=======================================
  Coverage   98.75%   98.76%           
=======================================
  Files           9        9           
  Lines        2405     2422   +17     
=======================================
+ Hits         2375     2392   +17     
  Misses         30       30           

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[iulusoy]

see comment at the line

[iulusoy]

I like your approach here, that you test if wind can be included in the data through the unit tests. But,
I think it would be more robust if the preprocessing steps would be set to True for the different options one by one and check that this does not affect the height coordinate. So I suggest to expand the test a bit with different settings dictionaries.