Service refactoring to "fully" enable segments (#19114)

* Refactor serverside content editing to support all variance combinations

* Fix build errors

* Reintroduce the tests ignored by #19060

---------

Co-authored-by: Mads Rasmussen <madsr@hey.com>

src/Umbraco.Core/Models/ContentEditing/ContentEditingModelBase.cs

@@ -2,9 +2,7 @@
 
 public abstract class ContentEditingModelBase
 {
-    public string? InvariantName { get; set; }
-
-    public IEnumerable<PropertyValueModel> InvariantProperties { get; set; } = Array.Empty<PropertyValueModel>();
+    public IEnumerable<PropertyValueModel> Properties { get; set; } = Array.Empty<PropertyValueModel>();
 
     public IEnumerable<VariantModel> Variants { get; set; } = Array.Empty<VariantModel>();
 }

src/Umbraco.Core/Models/ContentEditing/PropertyValueModel.cs

@@ -5,4 +5,8 @@ public class PropertyValueModel
     public required string Alias { get; set; }
 
     public required object? Value { get; set; }
+
+    public string? Culture { get; set; }
+
+    public string? Segment { get; set; }
 }

src/Umbraco.Core/Models/ContentEditing/VariantModel.cs

@@ -7,6 +7,4 @@ public class VariantModel
     public string? Segment { get; set; }
 
     public required string Name { get; set; }
-
-    public required IEnumerable<PropertyValueModel> Properties { get; set; }
 }

src/Umbraco.Core/Models/Validation/PropertyValidationContext.cs

@@ -8,7 +8,7 @@ public sealed class PropertyValidationContext
 
     public required IEnumerable<string> CulturesBeingValidated { get; init; }
 
-    public required IEnumerable<string> SegmentsBeingValidated { get; init; }
+    public required IEnumerable<string?> SegmentsBeingValidated { get; init; }
 
     public static PropertyValidationContext Empty() => new()
     {