fix: remove unused keyedService variable in AutofacRegistration.cs

Agent-Logs-Url: https://github.com/abpframework/abp/sessions/c39209b8-1bd6-4fae-b77b-ca167d8098b9

Co-authored-by: maliming <6908465+maliming@users.noreply.github.com>

Author: Copilot

framework/src/Volo.Abp.Autofac/Autofac/Extensions/DependencyInjection/AutofacRegistration.cs

@@ -337,7 +337,6 @@ private static void Register(
 
                     var serviceProvider = context.Resolve<IServiceProvider>();
 
-                    var keyedService = (Autofac.Core.KeyedService)requestContext.Service;
                     var key = requestContext.Parameters.KeyedServiceKey<object>();
 
                     return descriptor.KeyedImplementationFactory(serviceProvider, key);