code: function getDescriptionUrl(bid, components, prop) {
    if (config.getConfig('cache.url')) { return; }
  
    if (!deepAccess(components, `${prop}.description_url`)) {
      const vastUrl = bid && bid.vastUrl;
      if (vastUrl) { return encodeURIComponent(vastUrl); }
    } else {
      logError(`input cannnot contain description_url`);
    }
  }
docs: Returns the encoded vast url if it exists on a bid object, only if prebid-cache
  is disabled, and description_url is not already set on a given input
  @param {AdapterBidResponse} bid object to check for vast url
  @param {Object} components the object to check that description_url is NOT set on
  @param {string} prop the property of components that would contain description_url
  @return {string | undefined} The encoded vast url if it exists, or undefined