MM-54458 : Refactor playwright test with app areas (#24527)

e2e-tests/playwright/tests/functional/channels/search/find_channels.spec.ts

@@ -38,7 +38,7 @@ test('MM-T5424 Find channel search returns only 50 results when there are more t
 
     // # Click on "Find channel" and type "test_channel"
     if (pw.isSmallScreen()) {
-        await channelsPage.headerMobile.toggleSidebar();
+        await channelsPage.centerView.headerMobile.toggleSidebar();
     }
     await channelsPage.sidebarLeft.findChannelButton.click();