[NEP-18619]: Addressing review comments

Author: soundarya-mv

lib/superset/dashboard/datasets/list.rb

@@ -44,7 +44,8 @@ def datasets_details
           chart_dataset_ids = chart_datasets.map{|d| d['id'] }
           filter_dataset_ids_not_used_in_charts = filter_dataset_ids - chart_dataset_ids
           return chart_datasets if filter_dataset_ids_not_used_in_charts.empty?
-          dashboard_datasets = chart_datasets + filter_datasets(filter_dataset_ids_not_used_in_charts)
+          # returning chart and filter datasets
+          chart_datasets + filter_datasets(filter_dataset_ids_not_used_in_charts)
         end
 
         private