chore(lint): convert Storybook stories and shared utils to function components

Converts all .stories.tsx files across plugins and packages, plus
shared .storybook/shared utilities, from class components to function
components. No functional changes — purely structural cleanup.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

superset-frontend/plugins/plugin-chart-pivot-table/src/stories/PivotTable.stories.tsx

@@ -18,6 +18,7 @@
  */
 
 import { SuperChart, VizType } from '@superset-ui/core';
+import { supersetTheme } from '@apache-superset/core/ui';
 import { PivotTableChartPlugin } from '@superset-ui/plugin-chart-pivot-table';
 import { basicFormData, basicData } from './testData';
 import { withResizableChartDemo } from '@storybook-shared';
@@ -92,6 +93,7 @@ export const Basic = ({
   colSubtotalPosition: string;
 }) => (
   <SuperChart
+    theme={supersetTheme}
     chartType={VizType.PivotTable}
     datasource={{
       columnFormats: {},