https://shopify.dev/docs/apps/fulfillment/returns-apps/returns#step-1-query-returnable-fulfillments
follow the instructions,I can complete a return if I start request with api,my question is ,if my customer apply return request through the website with customer self-serve returns ,I cant get fulfillmentLineItemId for returnInput,its the id must have to create a return.Is there anyone know how to deal with it?