Mark a policy as global

curl --request POST \
  --url https://agentgateway-admin.dev.neuraltrust.ai/v1/gateways/{gateway_id}/policies/{id}/global \
  --header 'Authorization: <api-key>'

{
  "consumer_ids": [
    "<string>"
  ],
  "created_at": "<string>",
  "description": "<string>",
  "enabled": true,
  "gateway_id": "<string>",
  "global": true,
  "id": "<string>",
  "mode": "<string>",
  "name": "<string>",
  "parallel": true,
  "priority": 123,
  "settings": {},
  "slug": "<string>",
  "stages": [
    "<string>"
  ],
  "updated_at": "<string>"
}