[songs] Unable to add unlisted songs

[Fixator10]

If youtube video is unlisted, nightbot says “Video cannot be embedded”, however video embedding is enabled, and video is embeddable

Steps to reproduce:

1. Try to add any unlisted youtube song to “Song Requests” (example) (Video embed example)
2. Get “Video cannot be embedded”

Also, if video privacy is “Public” on adding, its works fine, even if it unlisted on play in queue

1. Get own youtube video
2. Change privacy to public
3. Add video to songs queue
4. Change privacy to unlisted
5. Video is playing fine

[night]

Out of an abundance of caution we disallow unlisted videos from being requested. Content might be confidential and could cause a leak.