Fix load more feature on the Account media gallery (#3293)

* Add load more button for large screens
* Fix `next` state value on the first loading
* Don't load if `isLoading || !hasMore`
* Start load on near the bottom

app/javascript/styles/components.scss

@@ -1962,6 +1962,7 @@ button.icon-button.active i.fa-retweet {
   text-align: center;
   padding: 15px;
   text-decoration: none;
+  clear: both;
 
   &:hover {
     background: lighten($ui-base-color, 2%);