applets/taskmanager: always show album art for single-window tooltips

The Task Manager tooltips now have logic to avoid showing album art for
tooltips where the window title doesn't include the media name. This
makes sense for the case of a multi-window app, where it almost
perfectly solves the problem of the album art appearing on all of the
tooltips rather than only the relevant one.

However this check does not make sense for single-window apps, where
the only thing it can do is cause an app to erroneously hide the album
art for playing media because the app doesn't include the media name
in its window title. Elisa is one such app, and there are probably
others too.
2 jobs for !720 with always-show-album-art-for-single-window-app-tooltips in 4 minutes and 54 seconds (queued for 6 seconds)
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