fix missing youtube videos with mislabled id

[gumaerc]

Pre-Flight checklist

• [ ] Testing
  • [ ] Code is tested
  • [ ] Changes have been manually tested

What are the relevant tickets?

Part of a fix for https://github.com/mitodl/ocw-data-parser/issues/193, doesn't completely close the issue

What's this PR do?

If you look at the attached issue, it's about a number of videos being missing from some courses. Upon investigation, it was found that these videos have embedded_media objects for their YouTube videos with an id property of copy_of_Video-YouTube-Stream. This PR simply adds this ID to VIDEO_EMBEDDED_MEDIA_IDS so that these videos aren't skipped over.

How should this be manually tested?

• Read the readme if you've never used ocw-to-hugo before and make sure you are set up to download courses from S3
• Place the following in private/courses.json:

  {
  "courses": [
  "18-01sc-single-variable-calculus-fall-2010",
  "cms-611j-creating-video-games-fall-2014"
  ]
  }

  • Run node . -i private/input -o private/output -c private/courses.json --download --rm
  • Search the private/input folder for the string copy_of_Video-YouTube-Stream and note the videos that this appears in
  • Check to make sure a corresponding markdown file has been created in the resources folder of the applicable course