MM-63669 E2E/Playwright: Move "e2e-tests/playwright/test" to "e2e-tests/playwright" folder (#30647)

* move "e2e-tests/playwright/test" to  "e2e-tests/playwright/test" and expose "ensurePluginsLoaded"

* add test setup, and expose ensurePluginsLoaded and ensureServerDeployment to pw

e2e-tests/playwright/specs/visual/common/landing_page.spec.ts

@@ -0,0 +1,13 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {test} from '@mattermost/playwright-lib';
+
+test('/landing#/login', async ({pw, page, browserName, viewport}, testInfo) => {
+    // Go to landing login page
+    await pw.landingLoginPage.goto();
+    await pw.landingLoginPage.toBeVisible();
+
+    // Match snapshot of landing page
+    await pw.matchSnapshot(testInfo, {page, browserName, viewport});
+});