related tags: refactor /related_tags.js to avoid updating unchanged columns.

Refactor the /related_tags.js call so that when the "Related tags"
button is clicked, it only replaces the columns that actually changed,
not the entire related tags section.

This avoids rebuilding the Recent / Frequent / Translated Tags / Artist
columns every time the "Related tags" button is clicked.

app/views/uploads/new.html.erb

@@ -104,7 +104,7 @@
           <%= submit_tag "Submit", :id => "submit-button", :class => "large ui-button ui-widget ui-corner-all gradient", data: {disable_with: false} %>
         </div>
 
-        <%= render "related_tags/container" %>
+        <%= render "related_tags/container", related_tags: nil %>
       <% end %>
     <% else %>
       <h2 style="margin-bottom: 1em;">You <%= CurrentUser.user.upload_limited_reason %></h2>