chore: make sure css output lands in app/assets/builds/dashboard

spec/dummy/app/assets/builds/dashboard/cable.js

@@ -1,17 +0,0 @@
-(() => {
-  var __getOwnPropNames = Object.getOwnPropertyNames;
-  var __commonJS = (cb, mod) => function __require() {
-    return mod || (0, cb[__getOwnPropNames(cb)[0]])((mod = { exports: {} }).exports, mod), mod.exports;
-  };
-
-  // app/javascript/cable.js
-  var require_cable = __commonJS({
-    "app/javascript/cable.js"(exports) {
-      (function() {
-        this.App || (this.App = {});
-        App.cable = ActionCable.createConsumer();
-      }).call(exports);
-    }
-  });
-  require_cable();
-})();