minor bug in cumulativetodeltaprocessor test (#34282)

**Description:** fixing a typo in cumulativetodeltaprocessor test code

**Link to tracking Issue:** N/A

**Testing:** N/A

**Documentation:** None

(feel free to incorporate it into another PR and reject this)

processor/cumulativetodeltaprocessor/processor_test.go

@@ -594,7 +594,7 @@ func generateTestHistogramMetrics(tm testHistogramMetric) pmetric.Metrics {
 			if tm.metricMins != nil {
 				mins := tm.metricMins[i]
 				if len(mins) > 0 {
-					dp.SetMin(sums[index])
+					dp.SetMin(mins[index])
 				}
 			}
 			if tm.metricMaxes != nil {