Wait some more for the close button to appear

During the warmup steps Media Viewer might take some time
to open, which might be why the close button won't appear in
less than 5 seconds

Change-Id: I3b17d46c3343f2b1ff33aaaf55faa4adb71cb218
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/618
Merge "Wait some more for the close button to appear"