FileUploadStrategy
type FileUploadStrategy =  | {      type: 'two_phase';    }  | {      type: 'direct';      uploadUrl: string;    };Strategy used to upload files referenced by composer attachments.
type FileUploadStrategy =  | {      type: 'two_phase';    }  | {      type: 'direct';      uploadUrl: string;    };Strategy used to upload files referenced by composer attachments.