Make `layout` nullable.

framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Components/LayoutHook/LayoutHookViewComponent.cs

@@ -16,7 +16,7 @@ public class LayoutHookViewComponent : AbpViewComponent
         Options = options.Value;
     }
 
-    public virtual IViewComponentResult Invoke(string name, string layout)
+    public virtual IViewComponentResult Invoke(string name, string? layout)
     {
         var hooks = Options.Hooks.GetOrDefault(name)?
             .Where(IsViewComponent)

framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Components/LayoutHook/ViewComponentHelperLayoutHookExtensions.cs

@@ -9,7 +9,7 @@ public static class ViewComponentHelperLayoutHookExtensions
     public static Task<IHtmlContent> InvokeLayoutHookAsync(
         this IViewComponentHelper componentHelper,
         string name,
-        string layout)
+        string? layout = null)
     {
         return componentHelper.InvokeAsync(
             typeof(LayoutHookViewComponent),