Swift Json Decoder how to get a nested part of the object without decoding it

I receive server response which contains geojson I need to have the geojson as string and don't want to decode it, but this code throws type mismatch exception.

init(from decoder: Decoder) throws {
    let container = try decoder.container(keyedBy: CodingKeys.self)
    id_s = try container.decode(String.self, forKey: .id_s)
    name = try container.decode(String.self, forKey: .name)
    description = try container.decode(String.self, forKey: .description)
    area_type = try container.decode(String.self, forKey: .area_type)
    active = String(try container.decode(Bool.self, forKey: .active))
    danger = String(try container.decode(Bool.self, forKey: .danger))
    scheduled_from = try container.decodeIfPresent(String.self, forKey: .scheduled_from)
    scheduled_to = try container.decodeIfPresent(String.self, forKey: .scheduled_to)
    
    let geojsonString = try container.decode(String.self, forKey: .geojson)
    // I need the raw geojson string, not a decoded dictionary
    // I get "Expected to decode String but found a dictionary instead"
}

I tried let geojson = try container.decode(String.self, forKey: .geojson) and et geojson = try container.decode(\[String, Any\].self, forKey: .geojson)