캠페인 일시정지

curl --request POST \
  --url https://client-api.tryvox.co/v2/campaigns/{campaign_id}/pause \
  --header 'Authorization: Bearer <token>'

{
  "campaign_id": "123",
  "ongoing_calls": 3,
  "paused_at": "2024-01-15T10:30:00Z",
  "paused_by": "user",
  "status": "paused",
  "success": true
}