DEV: Tweaks for drop-down implementation (#69)

- Remove unused 'toggleAiBotPanel' widget action

- Switch from appEvents to closure actions

- Convert widget definition to native class syntax, so that we can use `@action` decorator. (alternatively, we could have done `{ closePanel: this.hideAiBotPanel.bind(this) }` in `RenderGlimmer`

assets/javascripts/initializers/ai-bot-replies.js

@@ -24,10 +24,6 @@ function attachHeaderIcon(api) {
       this.state.botSelectorVisible = false;
     });
 
-    api.attachWidgetAction("header", "toggleAiBotPanel", function () {
-      this.state.botSelectorVisible = !this.state.botSelectorVisible;
-    });
-
     api.decorateWidget("header-icons:before", (helper) => {
       return helper.attach("header-dropdown", {
         title: "blog.start_gpt_chat",