Get campaign

{
    "success": true,
    "data": {
        "id": 1,
        "advert_id": 5,
        "advert_title": "Sample Ad",
        "broadcasting_type": "active_ad",
        "cpm": 1.5,
        "sending_limit": 1000,
        "sending_count": 250,
        "enabled": true,
        "created_at": "2024-01-01T00:00:00Z",
        "updated_at": "2024-01-15T10:30:00Z",
        "advert": {
            "id": 1,
            "name": "Sample Advertisement",
            "text": "This is a sample advertisement text",
            "pic_url": "https://example.com/image.jpg",
            "button_caption": "Click Me",
            "button_url": "https://example.com",
            "parse_mode": "HTML",
            "admitted": true,
            "created_at": "2024-01-01T00:00:00Z",
            "updated_at": "2024-01-15T10:30:00Z"
        }
    }
}