Implement assertion function in jsinterp

To perform additional checks and show error reasons in log.

Style fixes in jsinterp

Use the opposite operator != instead of not ==

force-test skip release

Fixes nsig decoding for player b22ef6e7 in YouTubeVideoUrl, thx bashonly

From: https://github.com/yt-dlp/yt-dlp/commit/297b0a379282a15c80d82d51f3757c961db2dae1

force-test

Use the function to get the default language

To call getLanguage() only once and perform all checks in this function.

Fix test on DASH MP4 format link

git1211

Fix test on DASH MP4 format link

Fix and improve expression parsing in jsinterp, thx dirkf

Improve BODMAS (fix player 590f65a6)
Support more weird expressions with multiple unary ops
Treat Infinity like NaN
Cache operator list

From: https://github.com/ytdl-org/youtube-dl/commit/fd8242e3efd3c0e2ba9a45c662d6983c00b21d6d
      https://github.com/ytdl-org/youtube-dl/commit/e0094e63c3bce919841b6e3634c877fcef8772a1

OAuth: optimize get_access_token and code style updates

git1208

OAuth: optimize get_access_token and code style updates

Does not use additional youtube oauth2 to get token

We can use the google accounts token to authenticate when extracting video links from youtube and therefore do not need to get an additional token from youtube.

Adds authentication when searching for videos, thx coletdjnz

This should prevent potential blocking when extracting video links.
So far no one has complained because it happens while downloading many links, but I have a feeling that it could be a problem in the future.
Also prevents variable stealing from YouTubeApi class in YouTubeMain.

YouTubeVideoUrl: replace use of a reluctant quantifier

git1201

YouTubeVideoUrl: replace use of a reluctant quantifier