Remove the account_id response attribute of video_website_card api

**Issue Type:** : Improvement

**Description:**

[The account_id response attribute of video_website_card api](https://github.com/twitterdev/twitter-ruby-ads-sdk/blob/master/lib/twitter-ads/creative/video_website_card.rb#L15) was removed in [Ads API Version 5](https://twittercommunity.com/t/ads-api-version-5/122353).