NsfwApiPolicy: Fall back more generously when functions don't match

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

@@ -92,6 +92,11 @@ def check_url_nsfw(%{"href" => url}) when is_binary(url) do
     check_url_nsfw(url)
   end
 
+  def check_url_nsfw(url) do
+    threshold = Config.get([@policy, :threshold])
+    {:sfw, %{url: url, score: nil, threshold: threshold}}
+  end
+
   def check_attachment_nsfw(%{"url" => urls} = attachment) when is_list(urls) do
     if Enum.all?(urls, &match?({:sfw, _}, check_url_nsfw(&1))) do
       {:sfw, attachment}
@@ -107,6 +112,8 @@ def check_attachment_nsfw(%{"url" => url} = attachment) when is_binary(url) do
     end
   end
 
+  def check_attachment_nsfw(attachment), do: {:sfw, attachment}
+
   def check_object_nsfw(%{"attachment" => attachments} = object) when is_list(attachments) do
     if Enum.all?(attachments, &match?({:sfw, _}, check_attachment_nsfw(&1))) do
       {:sfw, object}