Fixed sonar errors

Author: germanosin

api/src/main/java/io/kafbat/ui/service/metrics/scrape/prometheus/PrometheusTextFormatParser.java

@@ -39,11 +39,12 @@ public class PrometheusTextFormatParser {
   // Regex to capture metric name, optional labels, value, and optional timestamp.
   // Groups: 1=name, 2=labels (content), 3=value, 4=timestamp
   private static final Pattern METRIC_LINE_PATTERN = Pattern.compile(
-      "^([a-zA-Z_:][a-zA-Z0-9_:]*)"                     // Group 1: Metric name
-          + "(?:\\{(?>[^}]*)\\})?"                      // Group 2: Atomic label content
-          + "\\s+"
-          + "(-?(?:Inf|NaN|(?:\\d*\\.?\\d+(?:[eE][+-]?\\d+)?)))"  // Group 3: Value
-          + "(?:\\s+([0-9]+))?$");                      // Group 4: Optional timestamp
+      "^([a-zA-Z_:][a-zA-Z0-9_:]*)" +                        // Metric name
+      "(?:\\{(?>[^}]*)\\})?" +                               // Optional labels (atomic group)
+      "\\s+" +
+      "(-?(?:Inf|NaN|(?:\\d+(?:\\.\\d+)?(?:[eE][+-]?\\d+)?)))" +  // Metric value
+      "(?:\\s+([0-9]+))?$"                                   // Optional timestamp
+  );                // Group 4: Optional timestamp
 
 
   private static final Pattern HELP_PATTERN =