news preset: fix set-page scrolling
news preset: fix set-page scrolling

The set-page Layout.InfiniteScrolling should reference
the main subsets selection, not each individual subset
articles selection.

https://phabricator.endlessm.com/T12874

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