Update trace-mode-grafana.json (#2178)

* Update trace-mode-grafana.json

Update heatmap expression

* Update trace-mode-grafana.json

docs/en/setup/backend/telemetry/trace-mode-grafana.json

@@ -450,7 +450,7 @@
       "links": [],
       "targets": [
         {
-          "expr": "rate(trace_grpc_v6_in_latency_bucket[10m])",
+          "expr": "sum(rate(trace_grpc_v6_in_latency_bucket[10m])) by (le)",
           "format": "heatmap",
           "hide": false,
           "instant": false,
@@ -948,7 +948,7 @@
       "links": [],
       "targets": [
         {
-          "expr": "rate(persistence_timer_bulk_execute_latency_bucket[10m])",
+          "expr": "sum(rate(persistence_timer_bulk_execute_latency_bucket[10m])) by (le)",
           "format": "heatmap",
           "hide": false,
           "instant": false,
@@ -1200,4 +1200,4 @@
   "title": "SkyWalking trace-mode dashboard",
   "uid": "7NEmel8mk",
   "version": 17
-}
\ No newline at end of file
+}