unrotate_winds filter: fix failing tests #158
Description
During the migration of the rotate_winds and unrotate_winds filters from anemoi-datasets (PRs #150 and #151), tests were added based on mocked inputs for both filters in the absence of appropriate input data.
The unrotate_winds filters are currently failing (tests marked as xfail) due to an error: AttributeError: 'RegularDistinctLLGeography' object has no attribute 'latitudes_unrotated'.
It is unclear at this stage whether the test is failing due to either a bug in the code, or a misconfigured test. We should get appropriate input data to diagnose the issue, and either fix the filter or improve the test as necessary.