UDP parameterization problems with load_collection and filter_bands

@tbanyai brought this up in a use case he is working on:
if you try to parameterize the collection_id in load_collection() and/or band names in filter_bands() or band() you get into trouble because the current logic of filter_bands and band assumes there is metadata to normalize old band name aliases.
When collection_id or band names are parameterized, these method should not try to be too helpful with complaining that there is no metadata or that the band name is wrong

Start by inspecting load_collection(), filter_bands(), and band(), focusing on how they handle parameterized collection IDs and band names when metadata is unavailable. Confirm the current alias normalization and validation behavior, then ensure parameterized values are accepted without metadata-based complaints while normalizing known aliases when metadata exists.