Unflake `missing required html tags` test (#83328)
[Flakiness metric](https://app.datadoghq.com/ci/test/runs?query=test_level%3Atest%20env%3Aci%20%40git.repository.id%3Agithub.com%2Fvercel%2Fnext.js%20%40test.service%3Anextjs%20%40test.status%3Afail%20%40test.name%3A%22app-dir%20-%20missing%20required%20html%20tags%20should%20hmr%20when%20you%20fix%20the%20error%22%20%40git.branch%3Acanary&agg_m=count&agg_m_source=base&agg_t=count&citest_explorer_sort=timestamp%2Cdesc&cols=%40test.status%2Ctimestamp%2C%40test.suite%2C%40test.name%2C%40duration%2C%40test.service%2C%40git.branch¤tTab=overview&eventStack=&fromUser=false&index=citest&start=1755509670941&end=1756805670941&paused=false)
The test fixture already starts out with a missing tags error. This was not accounted for in the test, and could lead to the initial redbox being detected, instead of the one that appears after the layout was changed and the page was reloaded.
