server : add tooltips to settings and themes btn (#11154)

server : add tooltips to settings and themes btn (#11154)

* server : add tooltips to settings and themes btn

This commit adds tooltips to the settings and themes buttons in the
webui. The tooltip will be displayed below the actual buttons when
hovered over.

The motivation for this change is to clarify the purpose of the themes
button.

* squash! server : add tooltips to settings and themes btn

This commit adds a tooltip to the '...' button when a chat has been
started. The tooltip is "Chat options" which think could be a good
description as the dropdown contains options to delete or download the
current chat.

* rm tooltip for 3 dots button

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Co-authored-by: Xuan Son Nguyen <redacted>