Only downloads preview of video on manyvids even if logged in account has rights to full video

[globalgossamer]

Checklist

• [x] I'm reporting a broken site support
• [x] I've verified that I'm running youtube-dl version 2021.04.07
• [x] I've checked that all provided URLs are alive and playable in a browser
• [x] I've checked that all URLs and arguments with special characters are properly quoted or escaped
• [x] I've searched the bugtracker for similar issues including closed ones

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['--cookies', 'c.txt', '-v', 'https://www.manyvids.com/Video/1804307/Your-Cruel-Wife-Seduces-Her-Workmate/']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2021.04.07
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.19041
[debug] exe versions: ffmpeg 2021-02-16-git-8331eb058d-full_build-www.gyan.dev, ffprobe 2021-02-16-git-8331eb058d-full_build-www.gyan.dev
[debug] Proxy map: {}
[ManyVids] 1804307: Downloading webpage
[ManyVids] 1804307: Downloading webpage
[debug] Default format spec: bestvideo+bestaudio/best
[debug] Invoking downloader on 'https://dntgjk0do84uu.cloudfront.net/454058/o1e3q6sehj5idimd1651rqht8fb/preview/xxx.mp4

Description

When authenticated to manyvids, either with -u and -p, or with passing a cookie, youtube-dl will only grab the preview file (aka the free one). In this case the logged in user has rights to stream the full video, in compressed and original formats

[dirkf]

From https://github.com/ytdl-org/youtube-dl/pull/31172:

Please comment if this fixes the issue #28758, where a user could not download a paid video using cookies from a logged-in browser session. The extractor doesn't support username/password authentication.