Fix dzl-application-window startup warning
(epiphany:396483): dzl-application-window-CRITICAL **: 00:00:50.640: dzl_application_window_get_titlebar_animation: assertion 'DZL_IS_APPLICATION_WINDOW (self)' failed
During startup window is still unset, so there is no need to update the state. Once it is set the callback is called anyway.
Edited by Jan-Michael Brummer