Update Index.cshtml

Add missing directory to img path

Author: westin-m

4-WebApp-your-API/4-2-B2C/Client/Views/Home/Index.cshtml

@@ -9,4 +9,4 @@
         This sample shows how to secure a Web API built with ASP.NET Core using the Microsoft identity platform (formerly Azure Active Directory for developers).The client uses OpenID Connect to sign in users. It leverages the ASP.NET Core OpenID Connect middleware
         and MSAL.NET.
     </p>
-<img src="https://raw.githubusercontent.com/Azure-Samples/active-directory-aspnetcore-webapp-openidconnect-v2/master/4-WebApp-your-API/ReadmeFiles/topology.png"/>
+<img src="https://raw.githubusercontent.com/Azure-Samples/active-directory-aspnetcore-webapp-openidconnect-v2/master/4-WebApp-your-API/ReadmeFiles/4-2-B2C/topology.png"/>