V14/fix/element switch validation (#16421)

* Added Element <-> Document type switch validation

* Apply HasElementconfigured to block grid and block list

Fix smalle bug + optimization

* Moved some of the logic into warnings trough notifcationhandlers and eventmessages

* Cleanup

* Update openApi spec (merge changes)

* Add IsElement check between parent and child on creation

* Typos

* Transformed HasElementConfigured into HasElementConfigured

* Typo

Co-authored-by: Kenn Jacobsen <kja@umbraco.dk>

* IsElement Validation refactor

Moved validation logic regarding doctype IsElement switch into its own service as it will be consumed by more things down the line

* commit missing services...

* Naming improvements

* Bugfix

* First batch of integration tests for ElementSwitchValidator

* More integration tests!

* Little reformatting

* Changed the default values of block based configuration to match expected values.

---------

Co-authored-by: Kenn Jacobsen <kja@umbraco.dk>

src/Umbraco.Core/DependencyInjection/UmbracoBuilder.cs

@@ -398,11 +398,14 @@ namespace Umbraco.Cms.Core.DependencyInjection
 
             // Segments
             Services.AddUnique<ISegmentService, NoopSegmentService>();
-            
+
             // definition Import/export
             Services.AddUnique<ITemporaryFileToXmlImportService, TemporaryFileToXmlImportService>();
             Services.AddUnique<IContentTypeImportService, ContentTypeImportService>();
             Services.AddUnique<IMediaTypeImportService, MediaTypeImportService>();
+
+            // add validation services
+            Services.AddUnique<IElementSwitchValidator, ElementSwitchValidator>();
         }
     }
 }