Display webcomics on Stories landing page

[gestchild]

The stories landing page has a content list which allows the content editors to promote stories on the page.

However, if content of the deprecated 'webcomics' type is included then it won't appear on the page, because we don't fetch content of this type. We need to do this. See Slack conversation

N.B I'm not actually sure how the webcomic has been added as the content list should be locked down to articles and series as far as I can tell.