Custom Space level Templates are not editable

Issue Summary

Custom Space level Templates are not editable

Steps to Reproduce

1. Create a space level template with the old editor
2. save it
3. Try editing it and publishing it
   (Although, it is not possible to create a custom template with the old editor, now)

Expected Results

The templates should be editable.

Actual Results

The templates with the old editor are not editable.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available
If the legacy editor is not necessary for the template then, the same template can be re-created with the new editor.