fix(desktop): drop the "Edit message" tooltip from user bubbles

The bubble IS the edit button, so the native title popped up on hovering any
user message anywhere in the app. The aria-label stays, so the control keeps
its accessible name.

apps/desktop/src/components/assistant-ui/thread/user-message.tsx

@@ -348,7 +348,6 @@ export const UserMessage: FC<{
 
                         notifyThreadEditOpen()
                       }}
-                      title={copy.editMessage}
                       type="button"
                     >
                       {bubbleContent}