fix: API label casing and count value for +Inf bucket v2 metrics (#20656)

cmd/metrics-v2.go

@@ -1875,13 +1875,17 @@ func getHistogramMetrics(hist *prometheus.HistogramVec, desc MetricDescription,
 		// add metrics with +Inf label
 		labels1 := make(map[string]string)
 		for _, lp := range dtoMetric.GetLabel() {
-			labels1[*lp.Name] = *lp.Value
+			if *lp.Name == "api" && toLowerAPILabels {
+				labels1[*lp.Name] = strings.ToLower(*lp.Value)
+			} else {
+				labels1[*lp.Name] = *lp.Value
+			}
 		}
 		labels1["le"] = fmt.Sprintf("%.3f", math.Inf(+1))
 		metrics = append(metrics, MetricV2{
 			Description:    desc,
 			VariableLabels: labels1,
-			Value:          dtoMetric.Counter.GetValue(),
+			Value:          float64(dtoMetric.Histogram.GetSampleCount()),
 		})
 	}
 	return metrics