Feed sometimes shows the end of the feed on initial load

Feeds sometimes show the end of the feed on initial load: this makes it necessary to furiously scroll to the beginning to actually see the latest posts and is generally very annoying

This might be related to https://issuetracker.google.com/issues/180100692, https://stackoverflow.com/questions/65882817/paging-3-how-to-scroll-to-top-of-recyclerview-after-pagingdataadapter-has-fini

It broke the CI maybe 1 times out of 2 before I added the scrollToPosition(0) calls in the tests (which is the right thing to do because that's not what the tests are testing, but we should fix this issue...)