Remove extra Tab keypress that was causing test failure (#31817)

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

e2e-tests/playwright/specs/accessibility/channels/theme_settings.spec.ts

@@ -33,7 +33,6 @@ test('Theme settings should be keyboard accessible', async ({axe, pw}) => {
     await settingsModal.container.focus();
     await page.keyboard.press('Tab');
     await page.keyboard.press('Tab');
-    await page.keyboard.press('Tab');
     await page.keyboard.press('ArrowDown');
 
     // * The display tab should be open