Bump serialize-javascript and terser-webpack-plugin in /webpack-plugin (#5283)

Removes [serialize-javascript](https://github.com/yahoo/serialize-javascript). It's no longer used after updating ancestor dependency [terser-webpack-plugin](https://github.com/webpack/terser-webpack-plugin). These dependencies need to be updated together.


Removes `serialize-javascript`

Updates `terser-webpack-plugin` from 5.3.16 to 5.4.0
- [Release notes](https://github.com/webpack/terser-webpack-plugin/releases)
- [Changelog](https://github.com/webpack/terser-webpack-plugin/blob/main/CHANGELOG.md)
- [Commits](https://github.com/webpack/terser-webpack-plugin/compare/v5.3.16...v5.4.0)

---
updated-dependencies:
- dependency-name: serialize-javascript
  dependency-version: 
  dependency-type: indirect
- dependency-name: terser-webpack-plugin
  dependency-version: 5.4.0
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>