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/channels/intro_channel.spec.ts

@@ -0,0 +1,26 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {expect, test} from '@mattermost/playwright-lib';
+
+test('Intro to channel as regular user', async ({pw, browserName, viewport}, testInfo) => {
+    // Create and sign in a new user
+    const {user} = await pw.initSetup();
+
+    // Log in a user in new browser context
+    const {page, channelsPage} = await pw.testBrowser.login(user);
+
+    // Visit a default channel page
+    await channelsPage.goto();
+    await channelsPage.toBeVisible();
+
+    // Wait for Playbooks icon to be loaded in App bar, except in iphone
+    await expect(channelsPage.appBar.playbooksIcon).toBeVisible();
+
+    // Hide dynamic elements of Channels page
+    await pw.hideDynamicChannelsContent(page);
+
+    // Match snapshot of channel intro page
+    const testArgs = {page: page, browserName, viewport};
+    await pw.matchSnapshot(testInfo, testArgs);
+});