Revert "SerializeAsHTML(): Fallback to default ansi colors when running headless terminal"

[Tyriar]

Reverts #4196

This caused an issue when packaging v5.1:

assets by status 10.3 KiB [cached] 1 asset
./out/SerializeAddon.js 22.5 KiB [built] [code generated]

ERROR in ./out/SerializeAddon.js 4:23-63
Module not found: Error: Can't resolve 'browser/services/ThemeService' in '/home/vsts/work/1/s/addons/xterm-addon-serialize/out'
resolve 'browser/services/ThemeService' in '/home/vsts/work/1/s/addons/xterm-addon-serialize/out'
  Parsed request is a module
  using description file: /home/vsts/work/1/s/addons/xterm-addon-serialize/package.json (relative path: ./out)
    Field 'browser' doesn't contain a valid alias configuration
    resolve as module
      /home/vsts/work/1/s/addons/xterm-addon-serialize/out/node_modules doesn't exist or is not a directory
      /home/vsts/work/1/s/addons/xterm-addon-serialize/node_modules doesn't exist or is not a directory
      /home/vsts/work/1/s/addons/node_modules doesn't exist or is not a directory
      looking for modules in /home/vsts/work/1/s/node_modules
        /home/vsts/work/1/s/node_modules/browser doesn't exist
      /home/vsts/work/1/node_modules doesn't exist or is not a directory
      looking for modules in /home/vsts/work/node_modules
        /home/vsts/work/node_modules/browser doesn't exist
      /home/vsts/node_modules doesn't exist or is not a directory
      /home/node_modules doesn't exist or is not a directory
      /node_modules doesn't exist or is not a directory

webpack 5.61.0 compiled with 1 error in 747 ms
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! xterm-addon-serialize@0.9.0 package: `../../node_modules/.bin/webpack`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the xterm-addon-serialize@0.9.0 package script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/vsts/.npm/_logs/2022-12-19T18_07_51_333Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! xterm-addon-serialize@0.9.0 prepublishOnly: `npm run package`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the xterm-addon-serialize@0.9.0 prepublishOnly script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/vsts/.npm/_logs/2022-12-19T18_07_51_363Z-debug.log
Spawn exited with code 1
##[error]Bash exited with code '1'.

[silamon]

Any idea how to fix this? It's the import for DEFAULT_ANSI_COLORS that is making it fail. Duplicating the function to serialize addon seems not the right solution.

[Tyriar]

Something like this should do it:

https://github.com/Tyriar/xterm.js/blob/30ef1fcaa5b522e3d05ce000c63c7c5300970550/addons/xterm-addon-webgl/webpack.config.js#L24-L31

Almost made that change but I was trying to resolve the partial release asap. We should also try package as part of regular CI so we would catch this case in the future.