`/chals` does not always return all fields

May need to make an extra request for each challenge in order to get full details.

For example the following was only available at chals/14

{
  "category": "pwn",
  "description": "One binary, two challenges - double the fun\r\n\r\nmagic-pwn: Pwn me | magic-re: Reverse me\r\n\r\nnc magic.420blaze.in 420\r\n\r\nAuthor : DuSu",
  "files": [
    "f31e0df05311cd1d1cde11a897840623\/magic"
  ],
  "hidden": false,
  "hints": [
    
  ],
  "id": 14,
  "max_attempts": 0,
  "name": "magic-pwn",
  "tags": [
    
  ],
  "type": "standard",
  "type_data": {
    "id": "standard",
    "name": "standard",
    "scripts": {
      "create": "\/plugins\/challenges\/assets\/standard-challenge-create.js",
      "modal": "\/plugins\/challenges\/assets\/standard-challenge-modal.js",
      "update": "\/plugins\/challenges\/assets\/standard-challenge-update.js"
    },
    "templates": {
      "create": "\/plugins\/challenges\/assets\/standard-challenge-create.njk",
      "modal": "\/plugins\/challenges\/assets\/standard-challenge-modal.njk",
      "update": "\/plugins\/challenges\/assets\/standard-challenge-update.njk"
    }
  },
  "value": 420
}