Enable testnet4 unfurls

frontend/src/app/app-routing.module.ts

@@ -168,6 +168,10 @@ let routes: Routes = [
         path: 'testnet',
         loadChildren: () => import('./previews.module').then(m => m.PreviewsModule)
       },
+      {
+        path: 'testnet4',
+        loadChildren: () => import('./previews.module').then(m => m.PreviewsModule)
+      },
       {
         path: 'signet',
         loadChildren: () => import('./previews.module').then(m => m.PreviewsModule)