Handle error in the PageListBlockViewComponent when PageListBlock.Root references to the deleted page

Author: ihor-biletskyi

templates/Alloy.Mvc/Components/PageListBlockViewComponent.cs

@@ -45,6 +45,11 @@ private IEnumerable<PageData> FindPages(PageListBlock currentBlock)
         IEnumerable<PageData> pages;
         var listRoot = currentBlock.Root;
 
+        if (ContentReference.IsNullOrEmpty(listRoot))
+        {
+            return Enumerable.Empty<PageData>();
+        }
+
         if (currentBlock.Recursive)
         {
             if (currentBlock.PageTypeFilter is not null)