List all alerts

curl --request GET \
  --url https://api.getlago.com/api/v1/subscriptions/{external_id}/alerts \
  --header 'Authorization: Bearer <token>'

{
  "alerts": [
    {
      "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
      "lago_organization_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
      "subscription_external_id": "sub_1234567890",
      "customer_external_id": "cus_0987654321",
      "billable_metric": {
        "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
        "name": "Storage",
        "code": "storage",
        "description": "GB of storage used in my application",
        "recurring": false,
        "rounding_function": "round",
        "rounding_precision": 2,
        "created_at": "2022-09-14T16:35:31Z",
        "expression": "round((ended_at - started_at) * units)",
        "field_name": "gb",
        "aggregation_type": "sum_agg",
        "weighted_interval": "seconds",
        "filters": [
          {
            "key": "region",
            "values": [
              "us-east-1"
            ]
          }
        ]
      },
      "alert_type": "billable_metric_current_usage_amount",
      "code": "storage_threshold_alert",
      "name": "Storage Usage Alert",
      "previous_value": 1000,
      "last_processed_at": "2025-05-19T10:04:21Z",
      "thresholds": [
        {
          "code": "warn",
          "recurring": false,
          "value": "99.0"
        }
      ],
      "created_at": "2025-03-20T10:00:00Z"
    }
  ],
  "meta": {
    "current_page": 2,
    "next_page": 3,
    "prev_page": 1,
    "total_pages": 4,
    "total_count": 70
  }
}