[extractor/youtube] Extract more metadata for comments (#7179)

Adds new comment fields:
* `author_url` - The url to the comment author's page
* `author_is_verified` - Whether the author is verified on the platform
* `is_pinned` - Whether the comment is pinned to the top of the comments

Closes https://github.com/yt-dlp/yt-dlp/issues/5411

Authored by: coletdjnz