Not possible to set x-enum-varnames and other "well known" properties

[Demivan]

Describe the bug

Fix from #1993 (comment) is not possible to do now.

Version of NSwag toolchain, computer and .NET runtime used

NSwag 14.6.2
Dotnet 10

To Reproduce

public class EnumDocumentProcessor : IDocumentProcessor
{
	public void Process(DocumentProcessorContext context)
	{
		foreach (var schemaPair in context.Document.Components.Schemas)
		{
			var schema = schemaPair.Value;

			if (schema.IsEnumeration)
			{
				schema.ExtensionData ??= new Dictionary<string, object>();
				schema.ExtensionData.Add("x-enum-varnames", schema.EnumerationNames.ToArray());
			}
		}
	}
}

After applying this document processor, there are no x-enum-varnames in the schema.

Expected behavior

Adding properties to ExtensionData works.

Additional context

This is happening because there is EnumerationVarNamesRaw property that is mapped to x-enum-varnames. And because it is defined, data from ExtensionData is not used.