BHV-15102: Display SCRIM when popup is shown

SCRIM is made visible when the popup showing animation is complete.

Enyo-DCO-1.1-Signed-off-by: Anish Ramesan <anish.ramesan@lge.com>
Adding a TODO comment to remove this workaround once we have a
more fundamental fix in place.

Enyo-DCO-1.1-Signed-Off-By: Gray Norton (gray.norton@lge.com)
Merge pull request #1661 from enyojs/BHV-15102-anishramesan

BHV-15102: Display SCRIM when popup is shown

Reviewed-By: Aaron Tam (aaron.tam@lge.com)
Integrated-By: Gray Norton (gray.norton@lge.com)