[BHV-16348] Issue of co-existing Popup and contextual popup

Issue: If two different popups, both are extended from enyo.Popup exist
at the same time, it creates a conflict behavior as one popup doesn't
have information about the other's z-index.
Fix: The methods that removed that are overridden by moon. Popup and
moon.ContextualPopup
DCO-1.1-Signed-Off-By: Rajyavardhan P <rajyavardhan.p@lge.com>