MM-52641 MM-52645 Playwright/Accessibility: Initial setup and accessibility fix on login page (#23254)

* MM-52641 Playwright/Accessibility: initial setup

* upgrade Playwright to 1.36.1

* fix accessibility at login page

* fix lint

* update snapshot

e2e-tests/playwright/tests/accessibility/common/login.spec.ts

@@ -0,0 +1,19 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {expect, test} from '@e2e-support/test_fixture';
+
+test('/login', async ({pw, pages, page, axe}) => {
+    // # Go to login page
+    const {adminClient} = await pw.getAdminClient();
+    const adminConfig = await adminClient.getConfig();
+    const loginPage = new pages.LoginPage(page, adminConfig);
+    await loginPage.goto();
+    await loginPage.toBeVisible();
+
+    // # Analyze the page
+    const accessibilityScanResults = await axe.loginPage().analyze();
+
+    // * Should have no violation
+    expect(accessibilityScanResults.violations).toHaveLength(0);
+});