Have to choose between attachment or CC/BCC, can't be both

[changqing-cpf]

Describe the bug

This is for the programmatic email API.

In order to send attachment, have to use multipart/form-data. But when using multipart/form-data, there is no way to make cc or bcc an array.

Tried JSON.stringify, got the error message: "cc" must be an array.

Also tried cc[], got the error message: "cc[]" is not allowed

If I use application/json instead, can't send attachment.

Expected behavior

Parse multipart/form-data such that cc and bcc can be converted into an array. Alternatively, remove the array requirement for cc and bcc, and allow sending multiple cc and bcc form fields, like how attachments are implemented.