extend the wait_still_screen time in upgrade_pre too
    
    I have a better fix for this coming, but it's a big change that
    requires review, so for now, do this. The tests are actually
    failing because the 30 second wait_still_screen is too short(!)
    - it's triggering while the test is sitting at the 'full Fedora
    logo' bootsplash screen then doing a 30 second assert_screen
    graphical_login, which is failing because it actually takes
    more than 60 seconds to get from the 'full F' screen to the
    login screen. So let's just make the wait_still_screen 45
    seconds for now.