AbstractOfferPricingsImportRequest should have the shop param as optional

[andreico-am]

In AbstractOfferPricingsImportRequest the $shop param is required, but it should be nullable, as in the docs it is specified that shop_id is optional for PRI01. https://help.mirakl.net/help/api-doc/seller/mmp.html#PRI01

[jreinke]

Hello,

Thanks for the feedback, we are going to add a fix for this case.