mirage: Start ember-cli-mirage server only if window.startMirage is set

This will allow us to selectively enable Mirage only for some tests in the playwright test suite

Author: Turbo87

app/initializers/ember-cli-mirage.js

@@ -0,0 +1,20 @@
+import { importSync, isDevelopingApp, isTesting, macroCondition } from '@embroider/macros';
+
+export default {
+  name: 'ember-cli-mirage',
+  initialize(application) {
+    if (macroCondition(isTesting() || isDevelopingApp())) {
+      let startMirage = importSync('ember-cli-mirage/start-mirage').default;
+      let ENV = importSync('../config/environment').default;
+      let makeServer = importSync('../mirage/config').default;
+
+      application.register('mirage:make-server', makeServer, {
+        instantiate: false,
+      });
+
+      if (window.startMirage) {
+        startMirage(application.__container__, { makeServer, env: ENV });
+      }
+    }
+  },
+};

e2e/fixtures/mirage.ts

@@ -49,6 +49,7 @@ export class MiragePage {
   }
 
   async setup() {
+    await this.page.addInitScript('window.startMirage = true');
     await this.addHelpers();
   }
 }