fix(tab): fix event handler call

* switch event handler call to look at `event.isDefaultPrevented()` instead of
  `event.defaultPrevented` as angular has implemented that method on jqlite
  events.

Fixes angular-ui#5720

src/tabs/tabs.js

@@ -13,7 +13,7 @@ angular.module('ui.bootstrap.tabs', [])
         previousSelected.tab.onDeselect({
           $event: evt
         });
-        if (evt && evt.defaultPrevented) {
+        if (evt && evt.isDefaultPrevented()) {
           return;
         }
         previousSelected.tab.active = false;