ipatests: Fix UI_driver method after Selenium upgrade
    
    `WebDriver.switch_to_active_element()` was deprecated in favour of
    `driver.switch_to.active_element`.
    
    Method was deprecated a long time ago, however deprecation message and
    proxy method were removed recently and are not present in latest
    version.
    
    https://selenium-python.readthedocs.io/api.html#selenium.webdriver.remote.webdriver.WebDriver.switch_to_active_element
    https://www.selenium.dev/selenium/docs/api/py/webdriver_remote/selenium.webdriver.remote.webdriver.html#selenium.webdriver.remote.webdriver.WebDriver.switch_to
    
    Issue: https://pagure.io/freeipa/issue/9029
    
    Signed-off-by: Armando Neto <abiagion@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>