Fixed typo
Do not fire setAttributes when `editing-allowed` is not set.

`editing-allowed` is only set when in a completely learner-only course. This is to not potentially break existing behaviour when authoring, even though that behaviour may be erroneous.

Fixes e.g. the Markdown gadget giving 403 errors in the console.
Merge pull request #35 from Versal/no-setattributes-when-editing-not-allowed

No setattributes when editing not allowed