Reduce warnings created by WCS present when loading/write a NormalizedMetadata

[jmbhughes]

I noticed that a million warnings are created, one for each WCS keyword that's included but not expected. We should look into this and reduce the warnings. Here's an example: https://github.com/punch-mission/punchbowl/actions/runs/10361485767/job/28681893535?pr=224