fix usages to new names

Author: breedx-splk

ibm-mq-metrics/docs/metrics.md

@@ -106,7 +106,7 @@ public void run(QueueManager queueManager) {
           e.getMessage(),
           e);
     } finally {
-      if (this.metricsConfig.isMqHeartbeatEnabled()) {
+      if (this.metricsConfig.isIbmMqHeartbeatEnabled()) {
         heartbeatGauge.set(
             heartBeatMetricValue,
             Attributes.of(AttributeKey.stringKey("queue.manager"), queueManagerName));