R1:5b90567f6453

Persistent Chat: fix de-minimize misclick

Summary:
When the persistent chat is minimized to the bottom of your window, as mentioned in T15626,
the chat bar still has an invisible square area that does nothing if you click it by mistake:

{F2184778}

That area was reserved for the Settings Icon, that appears only if you de-minimize the chat.

The Settings Icon was toggled incorrectly from CSS. It was just hiding the Font Awesome icon,
(.fa-gear), instead of hiding its clickable container.

After this…