[Discover] Fix test skipped in elastic#193293 (elastic#194889)

## Summary

This PR fixes the test skipped in elastic#193293 after the Chrome 129 upgrade.
The issue was slightly less screen space causing the saved search save
popover to get in the way of the `@timestamp` column header, which we
were trying to click.

Flaky test runs:
-
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/7080

Part of elastic#193354.

### Checklist

- [ ] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [x] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [ ] Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard accessibility](https://webaim.org/techniques/keyboard/))
- [ ] Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [ ] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))
- [ ] This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)

### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

test/functional/apps/discover/group6/_time_field_column.ts

@@ -308,8 +308,7 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
             });
           });
 
-          // Fails in chrome 129+: https://github.com/elastic/kibana-operations/issues/199
-          it.skip('should render selected columns correctly', async () => {
+          it('should render selected columns correctly', async () => {
             await discover.selectTextBaseLang();
 
             await checkSelectedColumns({

test/functional/apps/discover/group6/index.ts

@@ -15,7 +15,7 @@ export default function ({ getService, loadTestFile }: FtrProviderContext) {
 
   describe('discover/group6', function () {
     before(async function () {
-      await browser.setWindowSize(1300, 800);
+      await browser.setWindowSize(1600, 1200);
     });
 
     after(async function unloadMakelogs() {