Imports: multi-part request content-type does not import

Improvement
Very minor, but it would be nice to have. When importing a multi-part request (in my case from Postman), it would be nice if the content-type for each part would import. Going to send you a sanitized request,
Just added this in my dev branch, so it'll be out this week
Done! https://yaak.app/blog/2024.5.0