fix(ivy): generate empty QueryList for root component content queries (#29514)

In View Engine, we used to generate empty QueryLists for content queries on root
components (though we did not actually support populating these lists). We need
to keep this behavior in Ivy for backwards compatibility. Otherwise, components
that are sometimes used as root will fail if they are relying on content query
results to always be defined.

PR Close #29514

packages/core/src/render3/component.ts

@@ -217,6 +217,12 @@ export function createRootComponent<T>(
     renderInitialStyles(native, rootTNode.stylingTemplate, componentView[RENDERER]);
   }
 
+  // We want to generate an empty QueryList for root content queries for backwards
+  // compatibility with ViewEngine.
+  if (componentDef.contentQueries) {
+    componentDef.contentQueries(RenderFlags.Create, component, rootView.length - 1);
+  }
+
   return component;
 }