When an episode from a show that has a cover is played. Switching to an
episode of a show that has no cover does not load the generic image in the
player. utils::set_image_from_path implementation does not deal with
DownloadError::NoImageLocation
utils::set_image_from_path deals with DownloadError::NoImageLocation,
this generic is set in this case.
https://gitlab.gnome.org/World/podcasts/issues/114
