Fix flaky TestPerLabelsetDiscardedSeriesTracker (#7036)

Signed-off-by: SungJin1212 <tjdwls1201@gmail.com>

Author: SungJin1212

pkg/util/discardedseries/perlabelset_tracker.go

@@ -81,9 +81,9 @@ func (t *DiscardedSeriesPerLabelsetTracker) Track(user string, series uint64, ma
 
 func (t *DiscardedSeriesPerLabelsetTracker) UpdateMetrics() {
 	usersToDelete := make([]string, 0)
-	labelsetsToDelete := make([]uint64, 0)
 	t.RLock()
 	for user, labelsetCounter := range t.userLabelsetMap {
+		labelsetsToDelete := make([]uint64, 0)
 		labelsetCounter.RLock()
 		if len(labelsetCounter.labelsetSeriesMap) == 0 {
 			usersToDelete = append(usersToDelete, user)

pkg/util/discardedseries/perlabelset_tracker_test.go

@@ -114,5 +114,5 @@ func TestPerLabelsetDiscardedSeriesTracker(t *testing.T) {
 
 func comparePerLabelsetSeriesVendedCount(t *testing.T, gaugeVec *prometheus.GaugeVec, user string, labelsetLimitId string, val int) {
 	gauge, _ := gaugeVec.GetMetricWithLabelValues("per_labelset_series_limit", user, labelsetLimitId)
-	require.Equal(t, testutil.ToFloat64(gauge), float64(val))
+	require.Equal(t, float64(val), testutil.ToFloat64(gauge))
 }