feat: check first entry of groupID instead of list length

Author: david-roper

apps/api/src/instrument-records/instrument-records.service.ts

@@ -160,7 +160,7 @@ export class InstrumentRecordsService {
           sessionType: record.session.type,
           subjectAge: record.subject.dateOfBirth ? yearsPassed(record.subject.dateOfBirth) : null,
           // eslint-disable-next-line perfectionist/sort-objects
-          groupId: record.subject.groupIds.length > 0 ? record.subject.groupIds.join(' ') : DEFAULT_GROUP_NAME,
+          groupId: record.subject.groupIds[0] ?? DEFAULT_GROUP_NAME,
           subjectId: record.subject.id,
           subjectSex: record.subject.sex,
           timestamp: record.date.toISOString(),