Searches the products of the store we are integrated with, for example to pick the item a customer wants in exchange.

• Shopify stores are searched live, so stock and available_for_sale are current. Each word of the query must
  match the start of a word in the product title, the vendor or a variant title, or the start of a SKU. Only
  active products are returned, with at most 25 variants each, so a product with more variants than that may
  be returned without the variant that matched.
• Custom integrations receive the query as the search text of their products endpoint, and define how it matches.
• BigCommerce stores are not supported and get a 400 response.

A successful request returns the list of found products.