Add patch to ActiveStorage::Blob#delete

Prevent deletion of variants. We don't currently use variants and this
causes timeouts (when doing a remote globs to find variant files to be
deleted) when using a ActiveStorage SFTP service.

See: https://github.com/rails/rails/blob/6-1-stable/activestorage/app/models/active_storage/blob.rb#L287-L290

lib/model_patches.rb

@@ -134,4 +134,14 @@ def disable
 
     prepend DisableWithProtection
   end
+
+  ActiveStorage::Blob.class_eval do
+    def delete
+      service.delete(key)
+      # Prevent deletion of variants. We don't currently use variants and this
+      # causes timeouts (when doing a remote globs to find variant files to be
+      # deleted) when using a ActiveStorage SFTP service
+      # service.delete_prefixed("variants/#{key}/") if image?
+    end
+  end
 end