How to set ApplicationUser Identity Custom Foreign Key on AspNetUsers table to nullable is false?

Code to follow. Is there a way to set the Application User : Identity custom foreign key to nullable : false using model builder net core?

Here is my application user class:

public class ApplicationUser : IdentityUser
    {
        [Required]
        public Company Company { get; set; }
        [Required]
        public int CompanyId { get; set; }
    }

Followed by the custom class:

public class Company : AuditableEntity
    {
        [Key]
        public int CompanyId { get; set; }
        [Required]
        public string CompanyName { get; set; }
        [Required]
        public string EmailAddress { get; set; }
        [Required]
        public string PhoneNumber { get; set; }
        public IEnumerable<ApplicationUser> ApplicationUsers { get; set; }
    }

With model builder:

protected override void OnModelCreating(ModelBuilder builder)
        {
            builder.Entity<ApplicationUser>()
                .HasOne(p => p.Company)
                .WithMany(b => b.ApplicationUsers)
                .OnDelete(DeleteBehavior.Cascade)
                .IsRequired()
                .HasForeignKey(p => p.CompanyId);

            builder.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());

            base.OnModelCreating(builder);
        }

With resulting migration:

migrationBuilder.CreateTable(
                name: "AspNetUsers",
                columns: table => new
                {
                    Id = table.Column<string>(nullable: false),
                    UserName = table.Column<string>(maxLength: 256, nullable: true),
                    NormalizedUserName = table.Column<string>(maxLength: 256, nullable: true),
                    Email = table.Column<string>(maxLength: 256, nullable: true),
                    NormalizedEmail = table.Column<string>(maxLength: 256, nullable: true),
                    EmailConfirmed = table.Column<bool>(nullable: false),
                    PasswordHash = table.Column<string>(nullable: true),
                    SecurityStamp = table.Column<string>(nullable: true),
                    ConcurrencyStamp = table.Column<string>(nullable: true),
                    PhoneNumber = table.Column<string>(nullable: true),
                    PhoneNumberConfirmed = table.Column<bool>(nullable: false),
                    TwoFactorEnabled = table.Column<bool>(nullable: false),
                    LockoutEnd = table.Column<DateTimeOffset>(nullable: true),
                    LockoutEnabled = table.Column<bool>(nullable: false),
                    AccessFailedCount = table.Column<int>(nullable: false),
                    Discriminator = table.Column<string>(nullable: false),
                    CompanyId = table.Column<int>(nullable: true) // NOTE NULLABLE HERE
                }

I've been searching through similar issues across previous questions, however I have yet to come across a solution/explanation. Any ideas?

Appreciate your time in advance.