Merge branch 'bugfix/notification-nil-actor' into 'develop'

notification_view.ex: Make sure `account` isn’t empty

See merge request pleroma/pleroma!1779

test/web/mastodon_api/views/notification_view_test.exs

@@ -100,5 +100,11 @@ defmodule Pleroma.Web.MastodonAPI.NotificationViewTest do
       NotificationView.render("index.json", %{notifications: [notification], for: followed})
 
     assert [expected] == result
+
+    User.perform(:delete, follower)
+    notification = Notification |> Repo.one() |> Repo.preload(:activity)
+
+    assert [] ==
+             NotificationView.render("index.json", %{notifications: [notification], for: followed})
   end
 end