Remove the area/editor label (#101682)

The project board github.com/grafana/grafana/projects/21 has been deleted
as far as I can tell (or never existed).

I can't see an obvious candidate-team to receive `area/editor`, so I
propose we delete it instead.

.github/commands.json

@@ -1115,14 +1115,6 @@
       "url": "https://github.com/orgs/grafana/projects/202"
     }
   },
-  {
-    "type": "label",
-    "name": "area/editor",
-    "action": "addToProject",
-    "addToProject": {
-      "url": "https://github.com/grafana/grafana/projects/21"
-    }
-  },
   {
     "type": "label",
     "name": "area/data/export",