extra hasPkAttribute check for isPrimaryKey

Added CheckForPkAttribute function to check if the object has a primary key attribute on one of the properties.
This function is used to determine if a property is a primarykey property.
This is a fix for having 2 primary key columns in the ModelDefinition for the following object.

public class Company
{
   public string CompanyName { get; set;}
   
   [AutoIncrement]
   [PrimaryKey]
   public byte CompanyID { get; set;}
}