Remove duplicate webhook registration (#18594)

Author: Zeegaan

src/Umbraco.Cms.Api.Management/DependencyInjection/UmbracoBuilderExtensions.cs

@@ -64,7 +64,6 @@ public static IUmbracoBuilder AddUmbracoManagementApi(this IUmbracoBuilder build
                 .AddWebhooks()
                 .AddServer()
                 .AddCorsPolicy()
-                .AddWebhooks()
                 .AddPreview()
                 .AddServerEvents()
                 .AddPasswordConfiguration()