Revert "refactor(@angular/ssr): handle promise-like results from loadChildrenHelper"

This reverts commit 64c74b4.

Author: alan-agius4

packages/angular/ssr/src/routes/ng-routes.ts

@@ -205,12 +205,7 @@ async function* handleRoute(options: {
           )
         : parentInjector;
 
-      const loadedChildRoutes = await loadChildrenHelper(
-        route,
-        compiler,
-        routeInjector,
-      ).toPromise();
-
+      const loadedChildRoutes = await loadChildrenHelper(route, compiler, routeInjector);
       if (loadedChildRoutes) {
         const { routes: childRoutes, injector = routeInjector } = loadedChildRoutes;
         yield* traverseRoutesConfig({