Ensure datasource configured sequence features preferences are honoured when features added via Fetch DB Refs or Show Cross-References operation

When a protein product/CDS alignment is shown, features are often added/propagated via cross-references to the sequences in the original view. For those new features, the sequence feature display should comply with datasource constraints (e.g. missense variants coloured red and appear at top of feature settings).

Specifically - retrieve from Uniprot, show Ensembl cross-reference should leave the original Uniprot view with appropriately coloured missence variants.