Changes to Batch merchant search

api operation id searchMerchants was added

removed the non-success response with the status 429

added the required property results/items/items/items/estimated_shipping/basis to the response with the 200 status

added the required property results/items/items/items/estimated_shipping/sample_size to the response with the 200 status

added the required property results/items/items/items/popularity_rank to the response with the 200 status