Appending custom claims when logging in via cookie with Asp.Net Core Identity

AccountController.cs

public class AccountController : Controller
{
    [HttpPost("login")]
    [AllowAnonymous]
    [ProducesResponseType(204)]
    [ProducesResponseType(400)]
    public async Task<IActionResult> Login([FromBody] LoginPost model)
    {
        var user = await _userManager.FindByEmailAsync(model.Identifier)
                   ?? await _userManager.FindByNameAsync(model.Identifier);
        if (user != null)
        {
            var passwordIsCorrect = await _userManager.CheckPasswordAsync(user, model.Password);
            if (passwordIsCorrect)
            {
                var customClaims = new []
                {
                    new Claim("logged_in_day", DateTime.UtcNow.DayOfWeek.ToString())
                };
                await _customClaimsCookieSignInHelper.SignInUserAsync(user, model.RememberMe, customClaims);
                _logger.LogInformation(1, "User logged in.");
                return NoContent();
            }
        }
        return BadRequest();
    }
}

CustomClaimsCookieSignInHelper.cs

using System.Collections.Generic;
using System.Security.Claims;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Identity;

namespace IdentityExtensions
{
    public class CustomClaimsCookieSignInHelper<TIdentityUser> where TIdentityUser : IdentityUser
    {
        private readonly SignInManager<TIdentityUser> _signInManager;

        public CustomClaimsCookieSignInHelper(SignInManager<TIdentityUser> signInManager)
        {
            _signInManager = signInManager;
        }

        public async Task SignInUserAsync(TIdentityUser user, bool isPersistent, IEnumerable<Claim> customClaims)
        {
            var claimsPrincipal = await _signInManager.CreateUserPrincipalAsync(user);
            if (customClaims != null && claimsPrincipal?.Identity is ClaimsIdentity claimsIdentity)
            {
                claimsIdentity.AddClaims(customClaims);
            }
            await _signInManager.Context.SignInAsync(IdentityConstants.ApplicationScheme,
                claimsPrincipal,
                new AuthenticationProperties {IsPersistent = isPersistent});
        }
    }
}