The type 'AssociationRegistry.Acm.Api.Infrastructure.ConfigurationBindings.AppSettings?' cannot be used as type parameter 'TService' in the generic type or method 'ServiceCollectionServiceExtensions.AddSingleton<TService>(IServiceCollection, TService)'. Nullability of type argument 'AssociationRegistry.Acm.Api.Infrastructure.ConfigurationBindings.AppSettings?' doesn't match 'class' constraint.