message: Fix durations not filtered for retention
  The initial durations list was not a constant and was overwritten for a default retention (6h). When server config is fetched, the first-pass filtering did already cause the loss of higher duration values.
  Fixes
diff: @@ -14,7 +14,7 @@ const toDurations = (tupleArray: [number, string][]): Durations => {
  return obj;
  };
  -let durationsTuples: [number, string][] = [
  +const durationsTuples: [number, string][] = [
  [60, 'Last 1m'],
  [300, 'Last 5m'],
  [600, 'Last 10m'],
  @@ -29,15 +29,16 @@ let durationsTuples: [number, string][] = [
  ];
  const computeValidDurations = (cfg: ComputedServerConfig) => {
  + let filtered = durationsTuples;
  if (cfg.prometheus.storageTsdbRetention) {
  // Make sure we'll keep at least one item
  if (cfg.prometheus.storageTsdbRetention <= durationsTuples[0][0]) {
  - durationsTuples = [durationsTuples[0]];
  + filtered = [durationsTuples[0]];
  } else {
  - durationsTuples = durationsTuples.filter(d => d[0] <= cfg.prometheus.storageTsdbRetention!);
  + filtered = durationsTuples.filter(d => d[0] <= cfg.prometheus.storageTsdbRetention!);
  }
  }
  - cfg.durations = toDurations(durationsTuples);
  + cfg.durations = toDurations(filtered);
  };
  // Set some defaults. Mainly used in tests, because
  