Make an unsubscribe group the default

Makes this group the organization's default: campaigns that name no group, and whose template and sending domain name none, unsubscribe recipients from it.

curl -X POST "https://example.com/v1/unsubscribe-groups/string/default"

{  "id": "string",  "organizationId": "string",  "name": "string",  "description": "string",  "isDefault": true,  "memberCount": 0,  "createdAt": "string",  "updatedAt": "string"}