HierarchicalSetModule: force first card set load
HierarchicalSetModule: force first card set load

Previously we added set cards, but they didn't become visible until the
scroll bar was moved. That was because the scrolled window decided it
needed content before any cards were added, so the show_more_content()
call did nothing. Trigger another show_more_content() operation when we
add set cards.

(Martin & Philip)

https://phabricator.endlessm.com/T10949

endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib