MM-63411 Don't focus thread textbox automatically when it has a draft (#31250)

* MM-63411 Don't focus thread textbox automatically when it has a draft

* Add E2E test

* Add test files forgotten in previous commit

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

e2e-tests/playwright/specs/functional/channels/threads/threads_list.spec.ts

@@ -0,0 +1,76 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {test} from '@mattermost/playwright-lib';
+
+test('Should be able to change threads with arrow keys', async ({pw}, testInfo) => {
+    test.skip(testInfo.project.name === 'ipad');
+
+    const {team, user} = await pw.initSetup();
+
+    const {channelsPage, page, threadsPage} = await pw.testBrowser.login(user);
+
+    await channelsPage.goto();
+    await channelsPage.toBeVisible();
+
+    // # Start some threads, and leave a draft in one of them
+    await channelsPage.centerView.postCreate.postMessage('aaa');
+    await (await channelsPage.getLastPost()).openAThread();
+    await channelsPage.sidebarRight.postMessage('aaa reply');
+
+    await channelsPage.centerView.postCreate.postMessage('bbb');
+    await (await channelsPage.getLastPost()).openAThread();
+    await channelsPage.sidebarRight.postMessage('bbb reply');
+    await channelsPage.sidebarRight.postCreate.writeMessage('bbb second reply');
+
+    await channelsPage.centerView.postCreate.postMessage('ccc');
+    await (await channelsPage.getLastPost()).openAThread();
+    await channelsPage.sidebarRight.postMessage('ccc reply');
+
+    // * Ensure that there's a draft
+    await channelsPage.sidebarLeft.draftsVisible();
+
+    // # Switch to the threads list
+    await threadsPage.goto(team.name);
+    await threadsPage.toBeVisible();
+
+    // * Ensure no thread starts selected
+    await threadsPage.toNotHaveThreadSelected();
+
+    // # Press the down arrow to select a thread
+    await page.keyboard.press('ArrowDown');
+
+    // * Ensure the latest thread was selected
+    await threadsPage.toHaveThreadSelected();
+    (await threadsPage.getLastPost()).toContainText('ccc reply');
+
+    // # Press the down arrow again
+    await page.keyboard.press('ArrowDown');
+
+    // * Ensure the latest thread was selected
+    await threadsPage.toHaveThreadSelected();
+    (await threadsPage.getLastPost()).toContainText('bbb reply');
+
+    await threadsPage.threadsList.focus();
+
+    // # Press the down arrow again
+    await page.keyboard.press('ArrowDown');
+
+    // * Ensure the latest thread was selected
+    await threadsPage.toHaveThreadSelected();
+    (await threadsPage.getLastPost()).toContainText('aaa reply');
+
+    // # Press the up arrow
+    await page.keyboard.press('ArrowUp');
+
+    // * Ensure the latest thread was selected
+    await threadsPage.toHaveThreadSelected();
+    (await threadsPage.getLastPost()).toContainText('bbb reply');
+
+    // # Press the up arrow
+    await page.keyboard.press('ArrowUp');
+
+    // * Ensure the latest thread was selected
+    await threadsPage.toHaveThreadSelected();
+    (await threadsPage.getLastPost()).toContainText('ccc reply');
+});