move unauth'd user blocks?/2 check

lib/pleroma/user.ex

@@ -882,6 +882,8 @@ def blocks?(%User{info: info} = _user, %{ap_id: ap_id}) do
       Pleroma.Web.ActivityPub.MRF.subdomain_match?(domain_blocks, host)
   end
 
+  def blocks?(nil, _), do: false
+
   def subscribed_to?(user, %{ap_id: ap_id}) do
     with %User{} = target <- get_cached_by_ap_id(ap_id) do
       Enum.member?(target.info.subscribers, user.ap_id)

lib/pleroma/web/mastodon_api/mastodon_api_controller.ex

@@ -884,14 +884,9 @@ def favourited_by(%{assigns: %{user: user}} = conn, %{"id" => id}) do
          %Object{data: %{"likes" => likes}} <- Object.normalize(object) do
       q = from(u in User, where: u.ap_id in ^likes)
 
-      users = Repo.all(q)
-
       users =
-        if is_nil(user) do
-          users
-        else
-          Enum.filter(users, &(not User.blocks?(user, &1)))
-        end
+        Repo.all(q)
+        |> Enum.filter(&(not User.blocks?(user, &1)))
 
       conn
       |> put_view(AccountView)
@@ -906,14 +901,9 @@ def reblogged_by(%{assigns: %{user: user}} = conn, %{"id" => id}) do
          %Object{data: %{"announcements" => announces}} <- Object.normalize(object) do
       q = from(u in User, where: u.ap_id in ^announces)
 
-      users = Repo.all(q)
-
       users =
-        if is_nil(user) do
-          users
-        else
-          Enum.filter(users, &(not User.blocks?(user, &1)))
-        end
+        Repo.all(q)
+        |> Enum.filter(&(not User.blocks?(user, &1)))
 
       conn
       |> put_view(AccountView)