[PM-15621] Refactor delete claimed user command (#6221)

- create vNext command
- restructure command to simplify logic
- move validation to a separate class
- implement result types using OneOf library and demo
  their use here

src/Api/AdminConsole/Models/Response/Organizations/OrganizationUserResponseModel.cs

@@ -236,8 +236,8 @@ public class OrganizationUserPublicKeyResponseModel : ResponseModel
 
 public class OrganizationUserBulkResponseModel : ResponseModel
 {
-    public OrganizationUserBulkResponseModel(Guid id, string error,
-        string obj = "OrganizationBulkConfirmResponseModel") : base(obj)
+    public OrganizationUserBulkResponseModel(Guid id, string error)
+        : base("OrganizationBulkConfirmResponseModel")
     {
         Id = id;
         Error = error;