fix(kafka): match KRaft controller dashboard panel to hashed pool name

The controller commit-latency panel selected controller pods with
pod=~"$strimzi_cluster_name-controller-.*", but the controller node pool
is named c-<hash> (kafka.controllerPoolName), so Strimzi names controller
pods <cluster>-c-<hash>-<id>. The literal -controller- never matched, so
the panel was permanently empty. Select the pool by its -c- token instead.

Signed-off-by: Andrey Kolkov <androndo@gmail.com>

dashboards/kafka/strimzi-kafka.json

@@ -2801,7 +2801,7 @@
       "targets": [
         {
           "datasource": "${DS_PROMETHEUS}",
-          "expr": "sum(kafka_server_raftmetrics_commit_latency_avg{namespace=\"$kubernetes_namespace\",pod=~\"$strimzi_cluster_name-controller-.*\"}) by (pod)",
+          "expr": "sum(kafka_server_raftmetrics_commit_latency_avg{namespace=\"$kubernetes_namespace\",pod=~\"$strimzi_cluster_name-c-.*\"}) by (pod)",
           "format": "time_series",
           "instant": false,
           "intervalFactor": 1,