Revert "Remove 'unlisted' handling for now."

This reverts commit 1027d1f696.

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -233,8 +233,7 @@ def fetch_public_activities(opts \\ %{}) do
     q = fetch_activities_query(["https://www.w3.org/ns/activitystreams#Public"], opts)
 
     q
-    # Too slow
-    # |> restrict_unlisted()
+    |> restrict_unlisted()
     |> Repo.all()
     |> Enum.reverse()
   end

test/web/activity_pub/activity_pub_test.exs

@@ -171,7 +171,6 @@ test "doesn't return blocked activities" do
   end
 
   describe "public fetch activities" do
-    @tag :skip
     test "doesn't retrieve unlisted activities" do
       user = insert(:user)
       {:ok, unlisted_activity} = CommonAPI.post(user, %{"status" => "yeah", "visibility" => "unlisted"})