News page doesn't load Tumblr items initially - requires reload

[pgleeson]

On first loading https://openworm.org/news.html (source for this is here: https://github.com/openworm/openworm.github.io/blob/master/news.html), a spinner with "Loading news from Tumblr..." is shown. Only on reloading the page is the list of news items from Tumblr shown.