Set WebApplication.New().ServerFeatures (#40183)

Author: feiyun0112

src/DefaultBuilder/src/WebApplication.cs

@@ -27,7 +27,7 @@ public sealed class WebApplication : IHost, IApplicationBuilder, IEndpointRouteB
     internal WebApplication(IHost host)
     {
         _host = host;
-        ApplicationBuilder = new ApplicationBuilder(host.Services);
+        ApplicationBuilder = new ApplicationBuilder(host.Services, ServerFeatures);
         Logger = host.Services.GetRequiredService<ILoggerFactory>().CreateLogger(Environment.ApplicationName);
 
         Properties[GlobalEndpointRouteBuilderKey] = this;

src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs

@@ -31,6 +31,16 @@ namespace Microsoft.AspNetCore.Tests;
 
 public class WebApplicationTests
 {
+    [Fact]
+    public async Task WebApplicationBuilder_New()
+    {
+        var builder = WebApplication.CreateBuilder(new string[] { "--urls", "http://localhost:5001" });
+
+        await using var app = builder.Build();
+        var newApp = (app as IApplicationBuilder).New();
+        Assert.NotNull(newApp.ServerFeatures);
+    }
+
     [Fact]
     public async Task WebApplicationBuilderConfiguration_IncludesCommandLineArguments()
     {