settings_users: Fix bot_list_widget not defined.

Fix error thrown when creating a bot if the bot_list_widget
is not defined.

static/js/settings_users.js

@@ -335,6 +335,10 @@ section.deactivated.create_table = (deactivated_users) => {
 };
 
 exports.update_bot_data = function (bot_user_id) {
+    if (!bot_list_widget) {
+        return;
+    }
+
     bot_list_widget.render_item(bot_user_id);
 };