[plotterparameter-helper] make sure badge is false if no plotter has been selected

Fixes #167

conda/js/src/helpers/schema/plotterparameter.json

@@ -16,5 +16,6 @@
                 "data": {
                         "$ref": "experiment#/definitions/parameter_set"
                 }
-        }
+        },
+		"required": ["plotter"]
 }