allView: Always update currentPage

Commit 0f178c3b3d added a shortcirtuit to avoid running
an animation on an invisible actor. However, it introduced
a bug where the current page is not properly updated. That
leads to the wrong set of icons being animated under some
circumstances.

Update the current page even if we bail out early.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/667

js/ui/appDisplay.js

@@ -467,6 +467,7 @@ var AllView = class AllView extends BaseAppView {
         if (!this.actor.mapped) {
             this._adjustment.value = this._grid.getPageY(pageNumber);
             this._pageIndicators.setCurrentPage(pageNumber);
+            this._grid.currentPage = pageNumber;
             return;
         }