Ancestral group Null representation inconsistency

[jdhayhurst]

Usually when ANCESTRY.ANCESTRAL_GROUP is given as NULL, it is displayed on the REST API and search UI as 'NR', e.g. https://www.ebi.ac.uk/gwas/rest/api/studies/GCST009376 and https://www.ebi.ac.uk/gwas/studies/GCST009376.

ancestries: [
{
type: "initial",
numberOfIndividuals: 774,
ancestralGroups: [
{
ancestralGroup: "NR"
}
],

However, for https://www.ebi.ac.uk/gwas/studies/GCST001338 this is not the case. It's presented correctly in the UI but on the REST API it's an empty array.

Need to investigate why it's not displayed as 'NR' for GCST001338 and correct it.

[jdhayhurst]

still an issue