Add missing xrefs for LSS variants.
Add missing xrefs for LSS variants.

* A parameter was missing, it was a bug
* See TRM-15522

ebi-uniprot/biojs-vis-proteinFeaturesViewer,ebi-uniprot/biojs-vis-proteinFeaturesViewer,ebi-uniprot/ProtVista,ebi-uniprot/ProtVista