Make ActionId a required field across DTOs and entities

Updated the `RecActionDto`, `RecAction`, and `InvokeRecActionCommandHandler` to enforce `ActionId` as a required field. This change improves data integrity by removing nullable `ActionId` properties and eliminates the need for null checks or null-forgiveness operators.

src/ReC.Domain/Entities/RecAction.cs

@@ -15,7 +15,7 @@ namespace ReC.Domain.Entities;
 public class RecAction
 {
     [Column("ACTION_ID")]
-    public long? ActionId { get; set; }
+    public required long ActionId { get; set; }
 
     [Column("PROFILE_ID")]
     public long? ProfileId { get; set; }