refactor: add an understanding of nullable for swagger gen

ApiDto/Responses/DisciplineResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents information about a discipline.
@@ -8,10 +10,12 @@ public class DisciplineResponse
     /// <summary>
     /// Gets or sets the unique identifier of the discipline.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the discipline.
     /// </summary>
+    [Required]
     public required string Name { get; set; }
 }