Updated mediawiki/extensions
Project: mediawiki/extensions/Echo  8912e9c7c91d40d9eb0e8350235b484e7fafa763

Remove qunit tests from mobile

ext.echo.overlay isn't loaded in mobile, so don't load the test in
mobile.

Bug: 69316
Change-Id: Iddd68aca84c69bed10a2afe4aea8463890485e26