fix(Player): Fix signature algorithm extraction

[absidue]

There is probably a cleaner way to handle this but this gets it working.

[bcomnes]

This fixes the YOUTUBEJS][Player]: Failed to extract signature decipher algorithm. stdout message when creating the player, but this doesn't seem to work with the onesierequest approach. All content 403s.

[Andrews54757]

I believe this is because the n-sig decipher is failing due to a missing variable.

fyn = function(J) {
    // ... nsig prelude.
    if (typeof uwg === "undefined") return J; // This is triggered because uwg is not defined
    // ...rest of nsig function.
}; fyn(nsig);

To fix, add this replace call:

nsig_function.result.replace(/if\(typeof [a-zA-Z0-9]*==="undefined"\)return [a-zA-Z0-9]*;/, '')

[absidue]

Okay so in conclusion this PR is working correctly, it's just that there are also issues with the nsig stuff that this PR wasn't intended to solve as it's for the sig stuff not nsig stuff.