[youtube] Check for incomplete data in watch initial data

[coletdjnz]

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Description of your pull request and other information

Currently observing YouTube giving incomplete data for this initial data occasionally, leading to missing metadata (and non-UTC upload date in some situations).

Added functionality so it falls back to the API in this case. In YoutubeTab we re-download the webpage in this case, but since the webpage in YoutubeIE is downloaded as part of the player response process it is probably easier to do it this way.

yt-dlp --print upload_date https://www.youtube.com/watch\?v\=tjjjtzRLHvA -v --proxy ''
[debug] Command-line config: ['--print', 'upload_date', 'https://www.youtube.com/watch?v=tjjjtzRLHvA', '-v', '--proxy', '']
[debug] User config "/home/coletdjnz/.config/yt-dlp.conf": ['--ffmpeg-location', '/opt/yt-dlp-ffmpeg']
[debug] Encodings: locale UTF-8, fs utf-8, pref UTF-8, out utf-8, error utf-8, screen utf-8
[debug] yt-dlp version stable@2023.03.04 [392389b7d] (source)
[debug] Lazy loading extractors is disabled
[debug] Git HEAD: c0de21bf7
[debug] Python 3.11.0rc2 (CPython x86_64 64bit) - Linux-5.19.17-2-MANJARO-x86_64-with-glibc2.37 (OpenSSL 1.1.1t  7 Feb 2023, glibc 2.37)
[debug] exe versions: ffmpeg N-107674-gf0abd07996-20220805 (setts), ffprobe N-107674-gf0abd07996-20220805, phantomjs 2.1.1, rtmpdump 2.4
[debug] Optional libraries: Cryptodome-3.15.0, certifi-2022.09.24, mutagen-1.46.0, sqlite3-2.6.0, websockets-10.4
[debug] Proxy map: {}
[debug] Plugin directories: ['/home/coletdjnz/.pyenv/versions/3.11.0rc2/envs/venv311rc2-ytdlp/lib/python3.11/site-packages/yt_dlp_plugins']
[debug] Loaded 1788 extractors
[youtube] Extracting URL: https://www.youtube.com/watch?v=tjjjtzRLHvA
[youtube] tjjjtzRLHvA: Downloading webpage
[youtube] tjjjtzRLHvA: Downloading android player API JSON
WARNING: [youtube] Incomplete data received in embedded initial data; re-fetching using API.
[youtube] tjjjtzRLHvA: Downloading initial data API JSON
[debug] Sort order given by extractor: quality, res, fps, hdr:12, source, vcodec:vp9.2, channels, acodec, lang, proto
[debug] Formats sorted by: hasvid, ie_pref, quality, res, fps, hdr:12(7), source, vcodec:vp9.2(10), channels, acodec, lang, proto, filesize, fs_approx, tbr, vbr, abr, asr, vext, aext, hasaud, id
[debug] Default format spec: bestvideo*+bestaudio/best
[info] tjjjtzRLHvA: Downloading 1 format(s): 247+251
20220323

Template

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• At least skimmed through contributing guidelines including yt-dlp coding conventions
• Searched the bugtracker for similar pull requests
• Checked the code with flake8 and ran relevant tests

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