fix(explore): rendering regression on standalone (#24177)

superset-frontend/src/explore/components/ExploreChartPanel/index.jsx

@@ -418,7 +418,11 @@ const ExploreChartPanel = ({
     if (!bodyClasses.includes(standaloneClass)) {
       document.body.className += ` ${standaloneClass}`;
     }
-    return standaloneChartBody;
+    return (
+      <div id="app" data-test="standalone-app" ref={resizeObserverRef}>
+        {standaloneChartBody}
+      </div>
+    );
   }
 
   return (

superset-frontend/src/explore/components/ExploreViewContainer/ExploreViewContainer.test.tsx

@@ -97,14 +97,19 @@ fetchMock.get('glob:*/api/v1/explore/form_data*', {});
 fetchMock.get('glob:*/api/v1/chart/favorite_status*', {
   result: [{ value: true }],
 });
+fetchMock.get('glob:*/api/v1/chart/*', {
+  result: {},
+});
 
 const defaultPath = '/explore/';
 const renderWithRouter = ({
   search = '',
   overridePathname,
+  initialState = reduxState,
 }: {
   search?: string;
   overridePathname?: string;
+  initialState?: object;
 } = {}) => {
   const path = overridePathname ?? defaultPath;
   Object.defineProperty(window, 'location', {
@@ -118,7 +123,7 @@ const renderWithRouter = ({
         <ExploreViewContainer />
       </Route>
     </MemoryRouter>,
-    { useRedux: true, initialState: reduxState },
+    { useRedux: true, initialState },
   );
 };
 
@@ -146,6 +151,16 @@ test('generates a new form_data param when none is available', async () => {
   replaceState.mockRestore();
 });
 
+test('renders chart in standalone mode', () => {
+  const { queryByTestId } = renderWithRouter({
+    initialState: {
+      ...reduxState,
+      explore: { ...reduxState.explore, standalone: true },
+    },
+  });
+  expect(queryByTestId('standalone-app')).toBeTruthy();
+});
+
 test('generates a different form_data param when one is provided and is mounting', async () => {
   const replaceState = jest.spyOn(window.history, 'replaceState');
   await waitFor(() => renderWithRouter({ search: SEARCH }));