Fix Firefox E2E CI gate

[vytas7]

It seems that something has got broken recently, so we had to disable these E2E tests on Firefox.
Was it Firefox 131.0, or anything in SeleniumBase? Or simply an issue with a new default GitHub Actions Ubuntu image?

You can find an example of a failed CI run here: https://github.com/falconry/falcon/actions/runs/11254279330/job/31291767229

__________________________________ test_chat ___________________________________

browser = <seleniumbase.plugins.pytest_plugin.sb.<locals>.BaseClass testMethod=base_method>
clear_log = <function clear_log.<locals>._impl at 0x7f7f0a27bc40>

    def test_chat(browser, clear_log):
        browser.slow_click('#button1')
>       browser.assert_text('Hello, WS1!', 'div.ws1', timeout=5)

e2e-tests/test_e2e.py:41: 

<...>

exception = <class 'selenium.common.exceptions.NoSuchElementException'>
message = 'Element {div.ws1} was not present after 5 seconds!'

    def timeout_exception(exception, message):
        exc, msg = shared_utils.format_exc(exception, message)
>       raise exc(msg)
E       seleniumbase.common.exceptions.NoSuchElementException: Message: 
E        Element {div.ws1} was not present after 5 seconds!