Move extension method

Move extension method to get the user Id out of the API module and into the authentication module.

Author: martincostello

src/TodoApp/ApiModule.cs

@@ -1,7 +1,6 @@
 // Copyright (c) Martin Costello, 2021. All rights reserved.
 // Licensed under the Apache 2.0 license. See the LICENSE file in the project root for full license information.
 
-using System.Security.Claims;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing;
@@ -100,9 +99,6 @@ public static IEndpointRouteBuilder MapApiRoutes(this IEndpointRouteBuilder buil
         private static string GetItemId(this HttpContext context)
             => (string)context.GetRouteValue("id")!;
 
-        private static string GetUserId(this HttpContext context)
-            => context.User.FindFirst(ClaimTypes.NameIdentifier)!.Value;
-
         private static ITodoService GetTodoService(this HttpContext context)
             => context.RequestServices.GetRequiredService<ITodoService>();
     }

src/TodoApp/AuthenticationModule.cs

@@ -60,6 +60,12 @@ public static IServiceCollection AddGitHubAuthentication(this IServiceCollection
         public static string GetProfileUrl(this ClaimsPrincipal user)
             => user.FindFirst(GitHubProfileClaim)!.Value;
 
+        public static string GetUserId(this HttpContext context)
+            => context.User.GetUserId();
+
+        public static string GetUserId(this ClaimsPrincipal user)
+            => user.FindFirst(ClaimTypes.NameIdentifier)!.Value;
+
         public static string GetUserName(this ClaimsPrincipal user)
             => user.FindFirst(GitHubAuthenticationConstants.Claims.Name)!.Value;