Updated management API endpoint and model for data type references to align with that used for documents, media etc. (#18905)

* Updated management API endpoint and model for data type references to align with that used for documents, media etc.

* Refactoring.

* Update src/Umbraco.Core/Constants-ReferenceTypes.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Fixed typos.

* Added id to tracked reference content type response.

* Updated OpenApi.json.

* Added missing updates.

* Renamed model and constants from code review feedback.

* Fix typo

* Fix multiple enumeration

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: mole <nikolajlauridsen@protonmail.ch>

src/Umbraco.Core/Models/RelationItem.cs

@@ -23,6 +23,9 @@ public class RelationItem
     [DataMember(Name = "published")]
     public bool? NodePublished { get; set; }
 
+    [DataMember(Name = "contentTypeKey")]
+    public Guid ContentTypeKey { get; set; }
+
     [DataMember(Name = "icon")]
     public string? ContentTypeIcon { get; set; }
 

src/Umbraco.Core/Models/RelationItemModel.cs

@@ -1,15 +1,19 @@
-namespace Umbraco.Cms.Core.Models;
+namespace Umbraco.Cms.Core.Models;
 
 public class RelationItemModel
 {
     public Guid NodeKey { get; set; }
 
+    public string? NodeAlias { get; set; }
+
     public string? NodeName { get; set; }
 
     public string? NodeType { get; set; }
 
     public bool? NodePublished { get; set; }
 
+    public Guid ContentTypeKey { get; set; }
+
     public string? ContentTypeIcon { get; set; }
 
     public string? ContentTypeAlias { get; set; }