Account for null Endpoint

Author: pranavkm

src/Security/Authorization/Policy/src/AuthorizationMiddleware.cs

@@ -47,7 +47,7 @@ public async Task Invoke(HttpContext context)
             var endpoint = context.GetEndpoint();
 
             // Workaround for https://github.com/aspnet/AspNetCore/issues/7011. Do not use the AuthorizationMiddleware for Razor Pages
-            if (endpoint.Metadata.Any(m => m.GetType().FullName == "Microsoft.AspNetCore.Mvc.ApplicationModels.PageRouteMetadata"))
+            if (endpoint != null && endpoint.Metadata.Any(m => m.GetType().FullName == "Microsoft.AspNetCore.Mvc.ApplicationModels.PageRouteMetadata"))
             {
                 await _next(context);
                 return;