Only use jQuery.tipsy for undo popover

Per discussion on Gerrit about previous patch-sets in this change, only use
jQuery.tipsy for the undo popover. This means that in the common case (i.e.,
the user has not just changed languages), the ULS tooltip will be system native
tooltip.

Change-Id: I9206a79d59687930c26b7ef86d29bfba050691fe

extension.json

@@ -197,7 +197,6 @@
 			"scripts": "js/ext.uls.interface.js",
 			"dependencies": [
 				"ext.uls.init",
-				"jquery.tipsy",
 				"mediawiki.jqueryMsg",
 				"mediawiki.user",
 				"ext.uls.webfonts"