Fix PackageAssemblyToCsv handling of non-Int Enums

[joelverhagen]

See dotnet/runtime#57531 (comment) for details.

The code in question is here:

Insights/src/Worker.Logic/CatalogScan/Drivers/PackageAssemblyToCsv/AssemblyAttributeReader.cs

Lines 216 to 233 in 2ee7cd5

	private class TypelessDecoder : ICustomAttributeTypeProvider<object>
	{
	private int _arrayCount;
	public int ArrayCount => _arrayCount;
	public object GetPrimitiveType(PrimitiveTypeCode typeCode) => null;
	public object GetSystemType() => null;
	public object GetSZArrayType(object elementType)
	{
	Interlocked.Increment(ref _arrayCount);
	return null;
	}
	public object GetTypeFromDefinition(MetadataReader reader, TypeDefinitionHandle handle, byte rawTypeKind) => null;
	public object GetTypeFromReference(MetadataReader reader, TypeReferenceHandle handle, byte rawTypeKind) => null;
	public object GetTypeFromSerializedName(string name) => null;
	public PrimitiveTypeCode GetUnderlyingEnumType(object type) => PrimitiveTypeCode.Int32;
	public bool IsSystemType(object type) => false;
	}