fix: address golangci-lint integer overflow warnings

Add bounds check before converting int to int32 in downscaleExponentialBucket
to prevent potential integer overflow issues detected by gosec linter.

Author: highlyavailable

exporters/prometheus/exporter.go

@@ -258,15 +258,21 @@ func downscaleExponentialBucket(bucket metricdata.ExponentialBucket, scaleDelta
 
 	// Process each bucket and accumulate counts into the appropriate downscaled bucket
 	for i := 0; i < len(bucket.Counts); i++ {
+		// Check if i can be safely converted to int32
+		if i > math.MaxInt32 {
+			continue // Skip if index is too large for int32
+		}
+
+		idx := int32(i)
 		// Calculate the original bucket index, with bounds check to prevent overflow
 		// Handle both positive and negative offsets
-		if bucket.Offset > 0 && int32(i) > math.MaxInt32-bucket.Offset {
+		if bucket.Offset > 0 && idx > math.MaxInt32-bucket.Offset {
 			continue // Skip buckets that would cause overflow
 		}
-		if bucket.Offset < 0 && int32(i) < math.MinInt32-bucket.Offset {
+		if bucket.Offset < 0 && idx < math.MinInt32-bucket.Offset {
 			continue // Skip buckets that would cause underflow
 		}
-		originalIdx := int32(i) + bucket.Offset
+		originalIdx := idx + bucket.Offset
 		// Calculate the downscaled bucket index
 		downscaledIdx := originalIdx >> scaleDelta
 		// Accumulate the count