fix(actionSheet): run $apply when closing actionSheet with back button

js/angular/service/actionSheet.js

@@ -150,7 +150,9 @@ function($rootScope, $document, $compile, $animate, $timeout, $ionicTemplateLoad
 
     // registerBackButtonAction returns a callback to deregister the action
     scope.$deregisterBackButton = $ionicPlatform.registerBackButtonAction(
-      scope.cancel,
+      function() {
+        $timeout(scope.cancel);
+      },
       PLATFORM_BACK_BUTTON_PRIORITY_ACTION_SHEET
     );