UX: makes smile the default emoji-picker icon (#30843)

discourse-emojis is used in chat only for message actions to show a
difference with the the other emojis so people don't think it's just the
smiley emoji.

plugins/chat/assets/javascripts/discourse/initializers/chat-setup.js

@@ -64,7 +64,7 @@ class ChatSetupInit {
           label: "chat.emoji",
           id: "emoji",
           class: "chat-emoji-btn",
-          icon: "discourse-emojis",
+          icon: "smile",
           position: "dropdown",
           displayed: owner.lookup("service:site").mobileView,
           action(context) {