Duplicate SendGrid Pre-built Design

**This endpoint allows you to duplicate one of the pre-built Twilio SendGrid designs**. Like duplicating one of your existing designs, you are not required to pass any data in the body of a request to this endpoint. If you choose to leave the `name` field blank, your duplicate will be assigned the name of the design it was copied from with the text "Duplicate: " prepended to it. This name change is only a convenience, as the duplicate design will be assigned a unique ID that differentiates i...