Update existing Custom Activity Type

The type's name, description, api_create_only, editable_with_roles and is_archived may be updated here. These properties will be updated immediately in the Custom Activity API.

Field order can be set here, but adding, modifying or removing fields from a Custom Activity Type must be done using the Custom Field API. The field order is a display property only, and does not affect the request and response for the Custom Activity API.