Updated mediawiki/extensions
Project: mediawiki/extensions/MobileFrontend  17694e3413fd9c5d77c663982621c36def518890

Regression: Don't load button and mainmenu styles twice in beta

ui.less loads both of these
uiNew.less shouldn't

Change-Id: I42542315a3d19bfe95f7f15f519361b21545dd9c