MediaWiki theme: Position PopupToolGroup indicator similar to other widgets
MediaWiki theme: Position PopupToolGroup indicator similar to other widgets

Use PopupToolGroup's handle indicator positioning like in widgets elsewhere.

Change-Id: I36538e3185e4968c478bb8107858f0404db7c67b

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui