support arbitrary order of variants of a product

[stmeissner]

Description

Right now the variants of product have to be listed in incremental order in the file to to be imported.

Expected Behavior

Variants given in arbitrary order should be accepted by the importer tool:

id	variantID
product-A	3
product-A	4
product-A	1
product-A	2

Current Behavior

In the current state it is not possible to import or update products when the variant IDs are not given in incremental order.

id	variantID
product-A	1
product-A	2
product-A	3
product-A	4

Context

Clients have to take extra effort to prepare the import file getting the sorting right. This is could be more user-friendly since the tool has all the information to create/update the product. The order of the variants shouldn't really matter.

[wizzy25]

@stmeissner Thanks for creating this issue. I'd like to have some more details of this; like what happens if the masterVariant (first variant) id is 1 and the other variants are in any arbitrary order?

[wizzy25]

Could this be related to #189? Cc @VasumathiJayakumar @Oehmi