test: activitypub: use User.invisible?/1 for testing invisibility

test/web/activity_pub/activity_pub_test.exs

@@ -182,7 +182,7 @@ test "it returns a user" do
     test "it returns a user that is invisible" do
       user_id = "http://mastodon.example.org/users/relay"
       {:ok, user} = ActivityPub.make_user_from_ap_id(user_id)
-      assert user.info.invisible
+      assert User.invisible?(user)
     end
 
     test "it fetches the appropriate tag-restricted posts" do