[Pleroma.Web.ActivityPub.Transmogrifier]: quick fix when tag is a Map

lib/pleroma/web/activity_pub/transmogrifier.ex

@@ -194,18 +194,22 @@ def fix_emoji(object) do
     object
   end
 
-  def fix_tag(object) do
+  def fix_tag(%{"tag" => tag} = object) when is_list(tag) do
     tags =
-      (object["tag"] || [])
+      tag
       |> Enum.filter(fn data -> data["type"] == "Hashtag" and data["name"] end)
       |> Enum.map(fn data -> String.slice(data["name"], 1..-1) end)
 
-    combined = (object["tag"] || []) ++ tags
+    combined = tag ++ tags
 
     object
     |> Map.put("tag", combined)
   end
 
+  def fix_tag(object) do
+    object
+  end
+
   # content map usually only has one language so this will do for now.
   def fix_content_map(%{"contentMap" => content_map} = object) do
     content_groups = Map.to_list(content_map)