[skip ci] Fix grafana dashboard expression (#10035)

Signed-off-by: NEdward Zeng <jie.zeng@zilliz.com>

deployments/monitor/grafana/milvus-dashboard.json

@@ -190,7 +190,7 @@
       "pluginVersion": "7.5.10",
       "targets": [
         {
-          "expr": "sum(milvus_rootcoord_create_collection_total{app_kubernetes_io_instance=~\"$instance\", app_kubernetes_io_name=\"$app_name\", namespace=\"$namespace\", type=\"total\"}) by (pod)",
+          "expr": "sum(milvus_rootcoord_create_collection_total{app_kubernetes_io_instance=~\"$instance\", app_kubernetes_io_name=\"$app_name\", namespace=\"$namespace\", type=\"total\"})",
           "instant": false,
           "interval": "",
           "intervalFactor": 2,