update for line_item_property with same variant ids 

with 'new' shopify line_item_property, items in the cart will be kept as separate lines with different properties however similar variants will keep same variant.id.  Therefore, removing by variant.id would remove all cart items of the same variant even though they may be different items by 'property' to the customer.  (to-date) using line= and forloop.index is the recommended approach