[BHV-14151]Scrim: Scrim is not preventing mouse hover event on Scroller

Issue: When Popup is showing scroller paging controls are getting focus
because of 'onenter' event.
Fix: "onenter" event is captured and handled within the popup if pop is
showing.
observation: though enter event is not triggered on the popup and its
contents when popup is showing. for safer side a checkpoint is given.
Enyo-DCO-1.1-Signed-off-by: Rajyavardhan P rajyavardhan.p@lge.com