DEV: Block accidental serialization of entire AR models (#27668)

plugins/chat/spec/plugin_helper.rb

@@ -113,6 +113,12 @@ module ChatSpecHelpers
   end
 
   def create_draft(channel, thread: nil, user: Discourse.system_user, data: { message: "draft" })
+    if data[:uploads]
+      data[:uploads] = data[:uploads].map do |upload|
+        UploadSerializer.new(upload, root: false).as_json
+      end
+    end
+
     result =
       ::Chat::UpsertDraft.call(
         guardian: user.guardian,