dashboards: undo hardcoded datasource

Author: snarlysodboxer

templates/cardano-parts-project/flake/opentofu/grafana/dashboards/cardano-blockperf.json

@@ -966,8 +966,7 @@
         },
         {
           "datasource": {
-            "type": "prometheus",
-            "uid": "mimir"
+            "type": "prometheus"
           },
           "editorMode": "code",
           "expr": "round(increase((time() - cardano_node_metrics_node_start_time_int{instance=~\"$instances\"} < bool 300)[1h:]))",
@@ -1254,4 +1253,4 @@
   "title": "Cardano Node: Block Performance",
   "uid": "ddvq1aojpkikgd",
   "version": 5
-}
+}