use `Filters` label as long as there is only one dataset

frontend/src/app/modules/work-package-graphs/configuration/wp-graph-configuration.service.ts

@@ -152,7 +152,7 @@ export class WpGraphConfigurationService {
     let queryTabs = this.configuration.queries.map((query) => {
       return {
         name: query.id as string,
-        title: this.I18n.t('js.chart.tabs.dataset', { number: 1 }),
+        title: this.I18n.t('js.work_packages.query.filters'),
         componentClass: WpGraphConfigurationFiltersTab
       };
     });

modules/dashboards/spec/features/work_package_graph_spec.rb

@@ -111,7 +111,7 @@ describe 'Arbitrary WorkPackage query graph widget dashboard', type: :feature, j
       # User has the ability to modify the query
 
       filter_area.configure_wp_table
-      modal.switch_to('Dataset 1')
+      modal.switch_to('Filters')
       filters.expect_filter_count(2)
       filters.add_filter_by('Type', 'is', type.name)
       modal.save
@@ -132,7 +132,7 @@ describe 'Arbitrary WorkPackage query graph widget dashboard', type: :feature, j
       dashboard_page.visit!
 
       filter_area.configure_wp_table
-      modal.switch_to('Dataset 1')
+      modal.switch_to('Filters')
 
       filters.expect_filter_count(3)