use the hbs plugin since we don't have gjs app templates

tests/app-template-minimal/vite.config.mjs

@@ -1,9 +1,10 @@
 import { defineConfig } from "vite";
-import { extensions, ember } from "@embroider/vite";
+import { extensions, ember, hbs } from "@embroider/vite";
 import { babel } from "@rollup/plugin-babel";
 
 export default defineConfig({
   plugins: [
+    hbs(),
     ember(),
     // extra plugins here
     babel({