chore(grafana): take back the messages in channel panel (#6665)

Signed-off-by: jsvisa <delweng@gmail.com>
Co-authored-by: Dan Cline <6798349+Rjected@users.noreply.github.com>

etc/grafana/dashboards/overview.json

@@ -4555,6 +4555,18 @@
                 "value": "negative-Y"
               }
             ]
+          },
+          {
+            "matcher": {
+              "id": "byFrameRefID",
+              "options": "C"
+            },
+            "properties": [
+              {
+                "id": "unit",
+                "value": "events"
+              }
+            ]
           }
         ]
       },
@@ -4602,6 +4614,18 @@
           "legendFormat": "Rx",
           "range": true,
           "refId": "B"
+        },
+        {
+          "datasource": {
+            "type": "prometheus",
+            "uid": "${DS_PROMETHEUS}"
+          },
+          "editorMode": "code",
+          "expr": "reth_network_pool_transactions_messages_sent{instance=~\"$instance\"} - reth_network_pool_transactions_messages_received{instance=~\"$instance\"}",
+          "hide": false,
+          "legendFormat": "Messages in channel",
+          "range": true,
+          "refId": "C"
         }
       ],
       "title": "Network transaction channel",