MRF: reject non-public: use pattern match to remove unnecessary if block

lib/pleroma/web/activity_pub/mrf/reject_non_public.ex

@@ -7,8 +7,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.RejectNonPublic do
   @allow_direct Keyword.get(@mrf_rejectnonpublic, :allow_direct)
 
   @impl true
-  def filter(object) do
+  def filter(%{"type" => "Create"} = object) do
-    if object["type"] == "Create" do
     user = User.get_cached_by_ap_id(object["actor"])
     public = "https://www.w3.org/ns/activitystreams#Public"
 
@@ -42,8 +41,8 @@ def filter(object) do
           _e -> {:reject, nil}
         end
     end
-    else
-      {:ok, object}
-    end
   end
+
+  @impl true
+  def filter(object), do: {:ok, object}
 end