Fix notification cannot be clicked in notifications page (#6439) [deploy]

* Avoid load more wrapper blocking clicks

The /notifications page shows a .load-more-wrapper
element that is blocking the .articles-list because
their z-index set to auto. Setting .articles-list‘s z-index
to 5 (align with its sibling .side-bar) and
.load-more-wrapper‘s z-index to 0.

* Update app/assets/stylesheets/notifications.scss

Co-Authored-By: ludwiczakpawel <ludwiczakpawel@gmail.com>

* Update app/assets/stylesheets/notifications.scss

Co-Authored-By: ludwiczakpawel <ludwiczakpawel@gmail.com>

Co-authored-by: ludwiczakpawel <ludwiczakpawel@gmail.com>

app/assets/stylesheets/notifications.scss

@@ -415,6 +415,8 @@
   }
 
   .load-more-wrapper {
+    clear: both;
+
     @include load-more;
 
     button {