[Version 15.1] Document to component drawer editing in experience manager causes a full iframe refresh

As a USER I would like to SEE a preview without reloading the iframe when switching from content to component editor

Acceptance criteria

Moving from editing a document to editing a component in the right-side editor drawer causes a full iframe refresh. I don't recall seeing this behavior in versions of PaaS.

Scope & technical Implementation

Because the preview in the iframe gets updated after each change in the right-side panel in the document, we have to reload the iframe only on the DISCARD action. 

In the scope of the implementation:

• DISCARD action is not passed from _askSaveOrDiscardChanges if no changes were made to the document
• Reloading of the iframe happens only on the DISCARD action