Remove the TextDecoder/TextEncoder polyfill

[cmdcolin]

Fixes #1553 by removing the TextDecoder polyfill we were using

It has different behavior to what exists on the proper https://developer.mozilla.org/en-US/docs/Web/API/TextDecoder

Hard exactly to tell why but the TextDecoder object we were receiving was not a proper instance of a TextDecoder

Possibly related to how this module allows multiple different ways of importing the module
https://github.com/anonyco/FastestSmallestTextEncoderDecoder

Note that caniuse says that all our browsers we target are ok without this https://caniuse.com/textencoder

[cmdcolin]

We can see that actually none of the variations specified in https://github.com/anonyco/FastestSmallestTextEncoderDecoder#api-documentation are based on calling new TextDecoder(), it suggests using new TextDecoder

[cmdcolin]

I'm going to remove this for now. It is somewhat mysterious here but otherwise it requires a revert to @gmod/tabix just because it is not compatible with this polyfill or something like this and I'd prefer if it was kept for now

[cmdcolin]

Note that simply installing fastestsmallesttextencoderdecoder to @gmod/tabix and importing it there does not work either, so the polyfill could be a problem?

[cmdcolin]

Follow up here if needed GMOD/tabix-js#123