UX: Admin setting page consistency - User API (#30610)

Create a basic config page that only contains user API-related settings, to replace the "user_api" category view linked to from "User API" in the admin sidebar.

app/assets/javascripts/admin/addon/routes/admin-config-user-api.js

@@ -0,0 +1,8 @@
+import DiscourseRoute from "discourse/routes/discourse";
+import { i18n } from "discourse-i18n";
+
+export default class AdminConfigUserApiRoute extends DiscourseRoute {
+  titleToken() {
+    return i18n("admin.advanced.sidebar_link.user_api");
+  }
+}