[YouTube] Fix extraction of age restricted videos

[B0pol]

• I carefully read the contribution guidelines and agree to them.
• I have tested the API against NewPipe.
• I agree to create a pull request for NewPipe as soon as possible to make it compatible with the changed API.

sts is no longer required so we no longer request /embed/:id to get sts

See ytdl-org/youtube-dl#29333

Closes #666, closes TeamNewPipe/NewPipe#6403

[AudricV]

The sts param is required to get cipher protected URLs: if some age-restricted URLs have signature ciphers, streams will return 403. So you should keep the sts param (I fixed its extraction in #604, don't fix it in this PR).

[B0pol]

The sts param is required to get cipher protected URLs: if some age-restricted URLs have signature ciphers, streams will return 403. So you should keep the sts param (I fixed its extraction in #604, don't fix it in this PR).

but sts is empty. it should be re-added if fixed IMO. Otherwise we'll be doing an useless request everytime there is an age restricted video / geo restricted / not available…

[TobiGr]

Does the sts extraction work for some videos? If that is the case, we should re-add the line. Otherwise, that can be done in #604

[B0pol]

No because the regex changed.

NewPipeExtractor/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamExtractor.java

Line 834 in 35c1bdd

return Parser.matchGroup1("\"sts\"\\s*:\\s*(\\d+)", embedPageContent);

fixed (in #604).

NewPipeExtractor/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamExtractor.java

Line 1033 in 5f4f123

sts = Parser.matchGroup1(STS_REGEX, playerCode);

NewPipeExtractor/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamExtractor.java

Line 693 in 5f4f123

private static final String STS_REGEX = "signatureTimestamp[=:](\\d+)";

[AudricV]

Just a small thing and this PR can be merged.