Fix the grip image on the comment dialog.
When we added the jquery-ui stylesheet, and upgraded jquery-ui, it broke

our custom grip image on the comment dialog. That image remained, but an

arrow overlayed it.
This brings it back, and in a cleaner way. We don't add it through

JavaScript anymore. Instead, we just set the CSS rule for that icon.
It now looks as it did in earlier versions.

Saw the dialog and played around with the grip. It looks and acts correctly again.