Client QPS指标的datasource配置项由"Prometheus"改为取$datasource参数

deployer/src/main/resources/metrics/Canal_instances_tmpl.json

@@ -938,7 +938,7 @@
       "bars": false,
       "dashLength": 10,
       "dashes": false,
-      "datasource": "Prometheus",
+      "datasource": "$datasource",
       "description": "client 请求的GET与ACK包的QPS。",
       "fill": 1,
       "gridPos": {