fix(backpressure): fix metric value of back pressure state (#2209)

fix: fix metric value of back pressure state

Signed-off-by: Ning Yu <ningyu@automq.com>

core/src/main/java/kafka/automq/backpressure/DefaultBackPressureManager.java

@@ -144,7 +144,7 @@ private void regulate(LoadLevel loadLevel, long now) {
     private Map<String, Integer> stateMetrics() {
         LoadLevel current = currentLoadLevel();
         for (LoadLevel level : LoadLevel.values()) {
-            int value = level.equals(current) ? 1 : -1;
+            int value = level.equals(current) ? current.ordinal() : -1;
             stateMetrics.put(level.name(), value);
         }
         return stateMetrics;