parseChartArtist function
Parses an artist from the charts data.
Implementation
JsonMap parseChartArtist(JsonMap data) {
  dynamic subscribers = getFlexColumnItem(data, 1);
  if (subscribers != null) {
    subscribers = (nav(subscribers, TEXT_RUN_TEXT) as String).split(' ')[0];
  }
  final parsed = <String, dynamic>{
    'title': nav(getFlexColumnItem(data, 0), TEXT_RUN_TEXT),
    'browseId': nav(data, NAVIGATION_BROWSE_ID),
    'subscribers': subscribers,
    'thumbnails': nav(data, THUMBNAILS),
  };
  parsed.addAll(parseRanking(data));
  return parsed;
}