Simplify column headers (#27557)

app/javascript/mastodon/features/ui/components/__tests__/column-test.jsx

@@ -1,13 +1,15 @@
-import { render, fireEvent, screen } from '@testing-library/react';
+import { render, fireEvent, screen } from 'mastodon/test_helpers';
 
 import Column from '../column';
 
+const fakeIcon = () => <span />;
+
 describe('<Column />', () => {
   describe('<ColumnHeader /> click handler', () => {
     it('runs the scroll animation if the column contains scrollable content', () => {
       const scrollToMock = jest.fn();
       const { container } = render(
-        <Column heading='notifications'>
+        <Column heading='notifications' icon='notifications' iconComponent={fakeIcon}>
           <div className='scrollable' />
         </Column>,
       );
@@ -17,7 +19,7 @@ describe('<Column />', () => {
     });
 
     it('does not try to scroll if there is no scrollable content', () => {
-      render(<Column heading='notifications' />);
+      render(<Column heading='notifications' icon='notifications' iconComponent={fakeIcon} />);
       fireEvent.click(screen.getByText('notifications'));
     });
   });