RavenDb Identity - UserManager DI not getting resolved

I am using RavenDb.Identity as my identity provider for a .Net 6 WebApi project. I am trying to seed user data and as part of that I need to access UserManager and RoleManager - like this

private readonly ILogger<DatabaseSeeder> _logger;        
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly RoleManager<ApplicationRole> _roleManager;

    public DatabaseSeeder( UserManager<ApplicationUser> userManager, RoleManager<ApplicationRole> roleManager,
        ILogger<DatabaseSeeder> logger)
    {
        _userManager = userManager;
        _roleManager = roleManager;            
        _logger = logger;            
    }

UserManager and RoleManager are supposed to be added to the DI in Program.cs from the following code

builder.Services.AddRavenDbDocStore() 
.AddRavenDbAsyncSession() 
.AddIdentity<ApplicationUser, ApplicationRole>(options =>
    {
        options.Password.RequiredLength = 8;
        options.Password.RequireDigit = false;
        options.Password.RequireLowercase = false;
        options.Password.RequireNonAlphanumeric = false;
        options.Password.RequireUppercase = false;
        options.User.RequireUniqueEmail = true;
    })
.AddRavenDbIdentityStores<ApplicationUser, ApplicationRole>();

But for some reason they are not getting added and I end up with the error message:

Cannot resolve 'Infrastructure.Seed.Identity.IDatabaseSeeder' from root provider because it requires scoped service 'Microsoft.AspNetCore.Identity.UserManager`1[Domain.Entities.Identity.ApplicationUser]'.

FYI: This is .Net 6 WebAPI project using WebApplicationBuilder.

Can you please help?