Fix demo translations (#2511)

* Fix demo translations

* Comment out some more panels

* Fix reference

demo/src/stubs/lovelace.ts

@@ -0,0 +1,28 @@
+import "../custom-cards/ha-demo-card";
+// Not duplicate, one is for typing.
+// tslint:disable-next-line
+import { HADemoCard } from "../custom-cards/ha-demo-card";
+import { MockHomeAssistant } from "../../../src/fake_data/provide_hass";
+import { HUIView } from "../../../src/panels/lovelace/hui-view";
+import { selectedDemoConfig } from "../configs/demo-configs";
+
+export const mockLovelace = (hass: MockHomeAssistant) => {
+  selectedDemoConfig.then((config) => hass.addEntities(config.entities()));
+
+  hass.mockWS("lovelace/config", () =>
+    selectedDemoConfig.then((config) => config.lovelace())
+  );
+
+  hass.mockWS("lovelace/config/save", () => Promise.resolve());
+};
+
+// Patch HUI-VIEW to make the lovelace object available to the demo card
+const oldCreateCard = HUIView.prototype.createCardElement;
+
+HUIView.prototype.createCardElement = function(config) {
+  const el = oldCreateCard.call(this, config);
+  if (el.tagName === "HA-DEMO-CARD") {
+    (el as HADemoCard).lovelace = this.lovelace;
+  }
+  return el;
+};