Implement validator for NewProductChooserField class. The validation will work:

• if enabledProductView==true && enabledCategoryView==true => product has to be selected (NewProductChooserBean.productId is not empty)
• else if enabledCategoryView==true => category has to be selected (NewProductChooserBean.categoryId is not empty)
• else => connection has to be selected (NewProductChooserBean.connection is not empty)
  The validator could be implemented by overriding getDefaultValidator() method in NewProductChooserField class.
  As part of the ticket is CSS styling of an error message to be visible on the field.