💄(frontend) updating the header and leftpanel for responsive

Previously we added a left panel. We now need to adapt the layout
so that it becomesresponsive.

We therefore add a burger menu on the left on mobile which,
when clicked, deploys the left-panel over all the content.

src/frontend/apps/e2e/__tests__/app-impress/header.spec.ts

@@ -75,29 +75,15 @@ test.describe('Header mobile', () => {
   test('it checks the header when mobile', async ({ page }) => {
     const header = page.locator('header').first();
 
+    await expect(header.getByLabel('Open the header menu')).toBeVisible();
+    await expect(
+      header.getByRole('link', { name: 'Docs Logo Docs' }),
+    ).toBeVisible();
     await expect(
       header.getByRole('button', {
         name: 'Les services de La Suite numérique',
       }),
     ).toBeVisible();
-
-    await expect(
-      page.getByRole('button', {
-        name: 'Logout',
-      }),
-    ).toBeHidden();
-
-    await expect(page.getByText('English')).toBeHidden();
-
-    await header.getByLabel('Open the header menu').click();
-
-    await expect(
-      page.getByRole('button', {
-        name: 'Logout',
-      }),
-    ).toBeVisible();
-
-    await expect(page.getByText('English')).toBeVisible();
   });
 });