Fix failing meteonorm tests

[kandersolar]

• [ ] Closes #xxxx
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• Tests added
• [ ] Updates entries in docs/sphinx/source/reference for API changes.
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The Meteonorm API slightly changed the return metadata text, causing our tests to fail. Example log: https://github.com/pvlib/pvlib-python/actions/runs/26162296722/job/76957024449

This PR makes the required minor updates to conform to the updated text.