PMM-12962 update metric name (#1588)

* PMM-12962 update metric name

* update title

dashboards/MongoDB/MongoDB_Cluster_Summary.json

@@ -1011,17 +1011,17 @@
       "pluginVersion": "8.3.5",
       "targets": [
         {
-          "expr": "min(mongodb_mongos_sharding_chunks_is_balanced{cluster=\"$cluster\"})",
+          "expr": "min(mongodb_mongos_sharding_chunks_is_balancer_running{cluster=\"$cluster\"})",
           "format": "time_series",
           "interval": "5m",
           "intervalFactor": 1,
-          "legendFormat": "Cluster Balanced",
+          "legendFormat": "Cluster Balancer is Running",
           "refId": "A",
           "step": 300
         }
       ],
       "timeFrom": "1m",
-      "title": "Chunks Balanced",
+      "title": "Chunks Balancer is running",
       "type": "stat"
     },
     {
@@ -1400,11 +1400,11 @@
         "y": 24
       },
       "type": "state-timeline",
-      "title": "Chunks Balanced",
+      "title": "Chunks Balancer is running",
       "description": "The MongoDB balancer is a background process that monitors the number of chunks on each shard. When the number of chunks on a given shard reaches specific migration thresholds, the balancer attempts to automatically migrate chunks between shards and reach an equal number of chunks per shard.",
       "targets": [
         {
-          "expr": "min(mongodb_mongos_sharding_chunks_is_balanced{cluster=\"$cluster\"})",
+          "expr": "min(mongodb_mongos_sharding_chunks_is_balancer_running{cluster=\"$cluster\"})",
           "interval": "$interval",
           "legendFormat": "$cluster",
           "refId": "A"