Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  fb28fd591eefeea6cc1026e77107b6d6ca640480

Integration tests for Client's Scribunto integration

This also removes the broken test mode handling from
WikibaseClient as that made it impossible to properly
inject a ClientStore mock.

Change-Id: I026fa93047f9564c997a4005952306c853ff5334