HtmlArticleGalleyPlugin does not manage issue galleys (OJS 3.3.0-13)

Describe the issue or problem
Hi, HtmlArticleGalleyPlugin does not work with issue galleys, they are downloaded and not rendered and published

Steps I took leading up to the issue
For example:

  1. upload a HTML issue galley in Issue Galleys
  2. publish the issue
  3. click the HTML issue galley
  4. the HTML galley is downloaded instead of opened and viewed
    image

What application are you using?
OJS 3.3.0-13

Additional information
We looked into the plugin: php and tpl are intended for articles only, we ask hints to extend the plugin to manage issues too