Confirmation message for leaving page edit mode should only be displayed after changes have been applied

Issue

• It is observed in vanilla version of Site Publisher, that when we close the "Edit Page" view (after we click on edit portlet (pencil icon) for a portlet but dont do any changes in the portlet's Edit mode dialog), we get the popup message - "Modifications have been made. Are you sure you want to close without saving?".

Expected Result:
The message "Modifications have been made. Are you sure you want to close without saving?" should only be shown if we made changes in any portlet (through its respective Edit Mode UI) or in the page containers.